fyi, last I checked, majority best sellers on Nintendo's store were third party.

This is partly true. My nieces only have Kirby, Pokemon and Mario games for their Nintendo handhelds

I don't think it's true because many people got there start with nintendo.

I think the reason it's such a big thing with Nintendo is because.
1. The low install bases of GCN and Wii U. If not a lot of people have the systems, third-parties usually aren't as motivated and less for the audience to pick from. Minecraft was the only third-party game on Wii U to sell a million or more units, unless you count Lego City Undercover which was only a first-party game on Wii U and not its later ports. GCN on the other hand had several million-sellers: SoulCalibur II, Sonic Mega Collection, Sonic Adventure DX, Lego Star Wars, etc.
2. Nintendo games have a pedigree and appeal to the install base. Even if somebody's collection of games on a Nintendo system isn't the overwhelming amount (say 33 to 50 percent instead of 75 to 95 percent) that's still probably a larger percentage than the other platform brands. The data shows that PlayStation and Xbox players are not playing first-party games in the overwhelming amount that happens on Nintendo.
Nintendo users only buying Nintendo games, or even overwhelming buying them with only one or two third-party games is largely a false perception.

Well considering that 50% of the software sold on the switch is first party there is some grain of truth in it.
I wonder how much first party that Sony & Microsoft sell, Does anyone know?

Nintendo absolutely dominates the software charts, Sony & Microsoft must be so envious
https://en.wikipedia.org/wiki/List_of_best-selling_Nintendo_Switch_video_games
I'm surprised Minecraft is so low, true its missing a year of sales but it won't be anywhere near enough to break the top 20

Hm, just taking a look at my Switch library.... I'd say that's largely true (for myself obv)

Well it depends on the platform hardly. How appealing it is to play on it any game. This claim was in my case true for the Wii U. I mostly just bought it for the exclusives and didn't like the console itself too much. It's also true in case of my roommate who prefers to play any game on his stationary PC. Although the majority of retail titles I purchased for the Switch are from Nintendo, it isn't true for my library at all. Overall, only 1/4 of my Switch library are games from Nintendo. Counting f2p games I paid a small amount of money in, it's even only 20%. Why? Because I love to play games on it and even purchased games I own already elsewhere again to play them portable instead of my Ps5, Xbox or PC. Like Ori, Hades, the Darksiders or Persona series and so many more, that just rested on my other systems unplayed, because I didn't find the time on stationary systems to play or at least finish them.

You could argue for some the Steam Deck is now a better solution, but I'm still not convinced because it's too heavy and bulky, and I'd prefer even something more portable than the Switch Lite to be honest.

I can obviously speak only for myself, but on our Switch the games are around 80% Nintendo titles. We only really buy one or two games on the system a year, and when we do it's almost always a Nintendo developed/published title. Any multiplatform games we usually get either on PC or PlayStation.

Well... when Microsoft has bought every game development company, it'll be true of Xbox as well.

Actually Switch is very friendly to 3rd party developers, especially indies. Games companies just ignore Nintendo as a platform because they mostly don't know what to do with it.

This discussion came up before, had an old table about this I've just updated with the previous fiscal year.

Best case scenario for Third Party on Switch is that they're responsible for 54.5% of software sales, in reality it will be less than this as explained by the ^ comment in the image. PlayStation software over the past 6 fiscal years third party has been responsible for 83.5% of software sales.

So Switch users making a game purchase are generally pretty 1:1 on whether they buy either a first party or third party games, whereas on PlayStation it's more like 4:1 in favour of third party.

If we use these percentages and the tie ratio for the consoles we get the following:

The average PS4 user has purchased 10.1 third party games and 2 first party games.
The average Switch user has purchased 4.65 third party games and 3.9 first party games.

But Switch users are still buying a decent amount of third party games even if the percentage share is much less. There's more to be said about the distribution of third party sales. PlayStation get's multiple third party titles release every year that will sell over 5m copies on the platform, the same cannot be said for Switch. Switch users do buy third party titles but these sales are more spread over many AA and Indie titles. The Switch does not get AAA third party system sellers bar the occasional title like Monster Hunter Rise. A 10m third party seller on a Nintendo platform is practically unheard of. So it's more the big blockbusters that give this perception. Either Nintendo doesn't get them (CoD, RDR2, GTAV, Cyberpunk, AC, Elden Ring) or it gets an inferior version that sells worse (Fifa, Hogwarts).