I voted 60-70m in the poll linked in Mnementh's post.

I think it was 105 million I predicted.

I was hoping for 60 million, maybe at best the 3DS + Wii U numbers and I can say that I probably wouldn't have made any bets on those sales figures as the general consensus was that the Switch would not even reach those levels.

1. The Wii U was a complete flop and people were not sure about the Switch because it didn't have a gimmick like Nintendo's recent successes had used (dual screens, 3D effect or WiiMote). Nintendo hadn't made a successful hardcore gaming console since the SNES and nobody was thinking that Nintendo should try to compete against Sony/Microsoft for that turf again. The fusion concept was fairly novel, but Nintendo had tried something similar with the Wii U Gamepad and it wasn't clear that Nintendo could produce something sleek and cool enough for people to want to carry in their pockets alongside their IPhones. Also, nobody expected the Switch to be a capable home console that could actually produce equally impressive graphics as a portable unit and would actually end up being the system of choice for hardcore gamers. Everybody thought that it would have to dock on a pedestal to achieve decent graphics and that as a portable unit it wouldn't be that much further ahead of the 3DS, meaning that either the home console mode (more likely) or the portable mode would come across as an afterthought that would get abandoned over time.
2. The 3DS was losing steam very quickly to smartphone gaming. At the time, it appeared that smartphone gaming was the future for portable gaming. The hybrid concept was thought to be Nintendo's only hope to make a handheld system relevant in 2017. Nobody predicted that smartphone gaming was more of a fad and that the ball would return to Nintendo's court the way it has.
3. The impact of Nintendo's 2017 launch lineup. Nobody thought that BotW would be as incredible as it turned out to be. Nintendo's last few Zelda releases (Skyward Sword, Twilight Princess) were basically letdowns and Nintendo hadn't made a truly groundbreaking Zelda game since Ocarina of Time. When people saw Miyamoto playing BotW (Zelda U) in 2014, there were complaints that the game environment looked empty and that there wouldn't be much to do. Apartment from that one brief demo and a few teasers, there was very little information on BotW prior to the Switch and it was being marketed as a Wii U exclusive right up until the Switch's launch window. Making BotW multiplatform was seen as a cop-out by fans and people really weren't thinking about just how revolutionary this game would be for Nintendo and the industry at large. It's not an exaggeration to say that BotW is possibly the greatest game ever made and is one of the most transformative for the industry.
3. Nobody expected that Nintendo games would become the new cool with the general public in 2020 like it has. The Switch has gone from being a 80-100 million lifetime seller as it sat last year to being 150-200 million selling console this year and possibly the most successful gaming hardware ever released. Nobody saw a virus and a massive lockdown coming in 2020 that would turn society off the mature, Hollywood style zombie/shooter games and back to the carefree innocence of the Mushroom Kingdom that made Nintendo huge in the 80's.

And just speaking from memory, I guarantee that the consensus was that the Switch would likely sell considerably less than the 3DS + Wii U and that Nintendo would have to go third party sometime in this generation. There is no way that the average member on this site was predicting that the Switch would sell 80-100 million in 2016-early 2017. At the very least, successful predictions for the Switch were being kept very quiet prior to its launch. The vocal people were the ones saying that it would fail.

They have already started screwing things up, and making bad decisions.

No matter what happens, i am still amazed at how much egocentric and arrogant Nintendo can be, not even trying to learn from previous generations' mistakes and continuing the same path of making pretty few years support on a system and then totally ignoring it, despite knowing that they'll be the only one supporting their consoles due to the fact that they tend to lower in terms of specs of their hardware, become out of phase compared to their generation and then have no(weak) third party support at the end. 

I have no clue about what's happening at Nintendo, but as a first party they have been the laziest this year, and we are talking about the third/fourth year of the switch which is really early to drop a successful system like that. 

personally, i predict that they'll continue giving us what we supposedly like since everything is selling extremely well. years full of ports and remakes with one big entry every one or two years. Anyway, what has been left to port from the wiiU? XCX? they'll port it, and then they'll port the Wii games but this time with even more lazyness since they had the balls to sell us games internally emulated on switch from previous generations without dropping a sweat, so we might look forward to those kind of surprises in the future. we'll get obviously the remasters (Deluxe) of the remakes of both zeldas' on the WiiU and they'll call it fair for the 35 anniversary since shit already strated and had huge success with mario.
besides that,Useless it is to expect any third party support starting seconf half of 2021 since they'll all merge to the next gen and developping for the switch would compell them to have one or several teams dedicated to that which is not profitable.

So yeah, to summ it up, bad decisions are already being made, and have always been made by Nintendo, and since they tend to not learn from previous failures, they'll continue making them.

Here is an interesting thread that shows peoples thoughts about the Switch's success before it launched. Really, there were lots of 10 million lifetime predictions and these were not Nintendo haters who were making these predictions.  Even Nintendo was really low on its own forecast (which was probably deliberately optimistic when it was made).

https://gamrconnect.vgchartz.com/thread/225013/dfc-intelligence-believes-nintendo-switch-can-shift-40-million-units-by-2020/1/

To be completely honest, I wouldn't read it too much on this year's schedule from Nintendo. It is pretty obvious the pandemic affected them negatively, otherwise would make no sense why they waited to almost the end of the year to announce the Mario anniversary and on the exact same special broadcast announced that one of the titles would be released next year after the celebration is over. Also according to rumors, Pikmin 3 Deluxe and Mario 3D All-Stars were supposed to be released around the middle of the year, if these easy-to-port titles took so long to be out it is clear that something went wrong.

On the other hand, it would make sense for Nintendo to let Animal Crossing carry the 2020 and Age of Calamity carry the holiday to hold the more strong games for after the PS5 and the Series X released,so they could make their console look more competitive against the other consoles, and it would match Furukawa's speach about giving the Switch a longer livespan. But of course, that is just me assuming.

ah yes my infamous 2013 LTD thread

I think mine was somewhere between 81-83 million but I don't remember exactly.

I cant even remember what I was expecting.

I was definately expecting it to do a lot better than the Wii U and probably somewhere closer to what the 3DS would end. No matter, I did not expect it to explode like it did.

I think the timeline went something like this for me basically:

In 2017:
40-50 million lifetime was my original prediction (though I could have seen 30-35 mil as the minimum and 70-80 mil as the maximum as well, but 40-50 was more my safe estimate)

In late 2017/2018:
75-85 mil was my newest prediction

In 2019:
110-115 mil was my newest prediction

Now:
Now I'm prediction 130-145 mil

I think the way my predictions have changed each year is fairly reasonable, though then again, I guess you could also say it's less fun to update a prediction so consistently. At some point you have so much data it's not even bold or interesting anymore. Oh well!