meh as a switch owner I don't care about most of those games being on the switch

Just dance is not a high production game. It might garner high sales but they release that sometimes on 6-7 different platforms every single year. It is designed to be cheap to port, it is designed to be very easy to update for a yearly release, and minimal effort is put into updating every single year. But I'm pretty sure Nintendo could make a Just Dance-style game and Just Dance would suddenly take a dramatic hit in sales on Nintendo platforms.

I don't think Nintendo breaks out of their way of making games that much at all. Publishers have done things like practically wholesale copied Pokemon (like Robopon) and not seen a fraction of the success. The Nintendo name itself garners the attention of people on Nintendo platforms, and they're far more likely to buy a game that was published by Nintendo than they were if it wasn't. Mario and Rabbids Kingdom battle is a prime example of that.  XCOM-style games have never sold well on Nintendo platforms (at least in recent history) , but if you take that game and add the Mario IP to it, it sells millions. It's hard for third parties to compete with that.

Well, I'd argue that Civ is far more outside the norms of a typical gamer library than those above. It's the first title that I can recall relies on a practically pure-PC fanbase. Whereas the other titles you mentioned are on PC/XB1-PS4/Switch.

I would really love for Civ 6 to do well.  I know I am going to buy it, but I can't predict how many other people will buy it.  Historically strategy gamers on consoles have been a very passionate but niche crowd.  If a good strategy/tactics game comes out, then the resale price will just stay high forever and continue to go up, but rarely does it sell a lot of copies.  Strategy gamers also seem like a group that cares very little about graphics.  If the gameplay is good, then that is all that really matters.  So it is a good demographic for Switch, but I just don't know how many strategy gamers there are nowadays on consoles.  If there is any game that they will go for, then Civ 6 is it.

Look here at best selling games on PS4 and XB1.

That realy depends from game to game, but fact is that any game will have higher sales on same platform when install is bigger compared to when it was lower, even Killzone on PS4 now has higher sales than it did on in PS4s 1st year. You arguing against clear facts and logic.

Again we talked Sony vs Nintendo games, and most Nintendo Switch games have very good legs.

Exception? You have plenty of examples when we talk about Nintendo games on Switch, Zelda, MK8D, Odyssey, Splatoon2, 1-2 Switch, Kirby, DKTF...look at official numbers for top 10 best selling games and look at update for same games at end of this month.

https://www.nintendo.co.jp/ir/en/finance/software/index.html

Lol, you dont make any sense, offcourse that we cant know how much exactly Zelda TP would sell if Wii had install base of 50m instead of 105m, but we can say that certanly would have less sales than it did at end with 105m install base. Same goes for every Switch game, every Switch game will sell better with higher install base, espacily when we talk about Nintendo games that traditionally have very good legs.

No, it's totally meaningless comparing sales of games on platforms where one has 4x bigger install base, thats a fact. Attach rate has much more sense when you comparing sales of platforms with totally different install basis instead of sales numbers, it simple show how much some game is selling compared to its install base.

I'm not concerned with just the best selling games. I'm concerned with most multi-platform games. You made the claim that it's greater than 90%. Now back that up.

I'm not arguing against logic and facts. My point has been that for the vast majority of titles, the vast majority of their sales are within the first six months to a year. This is borne out again and again. It'll be difficult for you to find many examples where this is not true. Because of this fact, the install base actually has very little factor in the overall sales of a game title. I'm never claimed it was zero, I claimed it was insignificant to the point of being meaningless.

Yes, exceptions. I'm not just talking about the ten best selling games. I'm talking about the hundreds of games that don't have top 10 sales numbers ever, that don't continue to sell quarter after quarter, you know, 95%+ of a console's game library. Even popular titles in popular franchises, say Assassin's Creed: Odyssey (I can't help myself)  won't be selling millions of copies in 2019. Those games have no legs, and this is the status quo for again, 95%+ of a game console's library.

Can you say with certainty that Twilight Princess would have less sales if the Wii had 50 million in sales vs 105 million? I mean, it stands to reason that some of that extra 55 million would have bought the game. But how many? If it would only be a couple hundred thousand than that 55 million had an extremely low impact on sales, wouldn't it? That would mean that the extra user base didn't lead to meaningfully better sales.  Every Switch game won't sell meaningfully better with a higher install base, mostly because, again, for over 95% of games, they don't keep printing and printing copies of the games until literally no one buys them. Many games will have no higher sales 4 years after release than they will 2 years after release since there aren't any more copies to buy.

Just a simple rhetorical question: Is it possible to make a multi-platform game that sells 5 million copies on PS4 and 5 million copies on Switch? If yes, then install base has no factor if a multi-platform game has 5 million sales on PS4 and 800K on Switch. 4.2 more Switch users could have bought the game just like the 5 million PS4 users did, but they chose not to. And again, attach rate has absolutely no impact to the people that actually decide whether or not a game should be brought to Switch, so it should have no place in this conversation. It doesn't actually indicate anything meaningful, but unsurprisingly is a go-to argument for those who want to justify their lowered the expectations of some users on this site.

But best selling games are best examples, espacily when we talk about Nintendo vs Sony games sales.

I gave you examples of Switch games that will keep selling very good.

Again we talked Sony vs Nintendo games, and most Nintendo Switch games have very good legs.

Offcourse I can, same I can certainly say that every Switch game will have better sales when Switch has install base of 40m for instance. We cant know for sure how much, but thats not point, point is that Zelda TP would sell less in any case (if Wii install base was smaller) and that Switch games will sell more in any case (with bigger install base later). I never said that for instance if Zelda BotW now has sold 10m on install base of 20m, that it will sell 20m on install base of 40m, just a simple fact that would sell more in any case.

Point that "attach rate has absolutely no impact to the people that actually decide whether or not a game should be brought to Switch" doenst has anuthing with my point.

Can someone fill me in on why this is so hotly debated here? I figured the answer would be obvious to everyone (difference in power preventing many ports), but I guess not.

people like having pointless debates

  You made the claim that it's greater than 90%. You can't back that up with a handful of examples, you need to back it up with statistics based on the sales of hundreds of multi-platform games. So please go ahead.

The best selling games aren't the best examples because again, the vast majority of games don't sell like the top 5% do. Most Nintendo Switch games do not have very good legs. Only the handful you mentioned did. I'm not going to go back and check, but let's say you mentioned 10 games. According to Wikipedia there are over 1200 Nintendo Switch games. You're talking about less than 0.008% of the Switch's library, and using these titles to represent the entirety of it. I'm actually account for that other 95% + you're ignoring.

We can say with some certainty? Why is that? I've conceded that it's more than zero, but again, that doesn't tell us anything. But is it more than 100K? Can you be certain of that? How about 200K? 1 million? You have no idea. It is the point that we can't know how many, since  total game sales aren't directly related to a console's platform's total sales. You refuse to concede this, even though if there was a direct relationship you would be able to reasonably predict how many copies of a game would sell on a higher or lower install base. 

So if you think it's some grand point that if title A sells 2 million copies on the Switch when there's 20 million Switches sold and when the Switch hits 40 million sold, title A is at 2.1 million copies sold, and when the Switch hits 60 million sold it's at 2.15 million sold, and since 2.15 is greater than 2,  then that means that sales grow with install base, then you're making one of the frailest points in this thread. It's insignificant. It doesn't matter even a little bit.  it doesn't show that install base impacts sales in any meaningful way any more than time does. For all you know those 150K sold after those two milestones were hit were all bought by people who owned the console when it hit the 20 million milestone, which again, would mean the extra 40 million switches sold made zero impact on sales. So the best you can say about the impact install base has on a game is that it may have some immeasurable impact. If you want to get hung up on that, that's on you.

Well the reason you keep bringing up attach rate is you think that it justifies third party sales that for higher budget, expensive to port games don't instill confidence that there's money to be made. The question the OP asks is why big games aren't coming to the Switch. Attach rate has literally nothing to do with that.