Nintendo Switch is perfectly viable as a primary or even only gaming device...

[Mnementh]

Well, you don't have to convince me. Switch is currently my primary gaming platform, my Linux-PC my secondary. And my backlog is ever increasing.

But there are some reasons why Switch might not be enough.

1. You like big action games, shooters or sports games. Without a doubt the Switch is bad in these categories, although it looks a bit better in the action department, but still there is much more on the other consoles. If you on the other hand like instead adventures, metroidvania or platformers the Switch is obviously better than any other platforms. For me I don't have any interest in Sports games, get enough action games on Switch and have only occasional urge for shooters which Doom satisfies well enough.

2. You like extraordinarily one of the exclusives on other platforms or a multiplat that is missing the Switch. This is usually the main argument to own a Nintendo console, but it works as well for the other consoles. Who wants Red Dead Redemption 2 is not looking fondly on the Switch. For me personally - my taste in games is stuck somewhat back in the past, I didn't follow modern trends. So I don't care much for most of the games. I kinda miss out on Witcher 3, but basically that urge can be satisfied enough with games like Zelda. Other than that nothing really speaks to me which is missing Switch. Yeah, if I had RDR2 I would give it a try, but I don't care too much. I tried GTAV because everyone was so into that, and it bored me to death. So I'm not too hot on another Rockstar game.

3. You might look down on Nintendo games, indies and genres besides the action and shooter stuff. Therefore Civ VI (which is a big deal for me personally) does nothing for you, you scoff at Undertale and Hollow Knight and Mario looks silly and childish. As I'm one of the older gamers, I'm over these stuff. I like games that entertain me. Does the game look silly or childish? I don't care, I'm sure enough of my adulthood, that I can admit that Eevee is totally cute and I just enjoy leaving the start screen of Let's Go on for a few seconds to enjoy how Eevee jumps around without a care in the world. Yeah, as a teenager I too was anxious to look mature. But I got over it. Same with indies. I don't need the validation of the peer group to play the same game as everyone. I can pick up a total indie game and enjoy the hell out of it.

4. You don't have to work or generally more than enough time so that you constantly need new games to be entertained. Probably most consoles don't work for you alone, but maybe a console with more and bigger games take precedence over the Switch then. I have work and also have other interests like movies and books, so my gaming time is restricted. I also like to play slow and take my time in games. Therefore I don't get through games that fast.