There are great games on other consoles, which is why my PS4 Pro is my SIDE console. However if I only had a Switch, there are plenty of other full retail ports that I could play to keep busy.
South Park games
Valkeria Chronicles 4
Crash N Sane
Starlink Battle for Atlus
Just to name a few. This is on top of other exclusives the Switch may have. Sure I would miss out on games like Horizon or God of War, but in no way would I have a shortsge of games to play. I can say this because I own Red Dead 2, but I have enough games to focus on with my Switch and portability is a factor for me, to where I have yet to even play the game. In no way do I feel unhappy about this decision.
Now missing out on games can also be used against any console as well. If you are a Sony only gamer, you get no Mario, Zelda, Smash, Octopath, Xenoblade, Bayonetta, Metroid, etc. This works both ways, even for XBox to an extent.
Well that's why Im not a Sony only gamer either. I play all three. Although the Xbox brand is starting to lose its appeal to me. Hopefully they will be better next gen.
If you are satisfied with the Switch only, then it seems like you either have a very broad taste in games or you have little time to play games. The highs of the Switch, like Mario Odyssey and BOTW are amazing, but they are too far apart for me. Earlier next year Im really excited for Resident Evil 2, Kingdom Hearts 3, Sekiro, DMC5 and some others Im interested in. If I was only a Switch gamer I would be stuck with what during that time? The 6 year old 60$ game NSMBUD and maybe Fire Emblem and Yoshi? Yeah, no thanks.