The Switch isn't cheap by any stretch of the imagination, I agree, but as you said, some people want Nintendo exclusives, so they buy a Switch as their primary gaming device and don't have the desire / time / money to buy another. It makes no sense for these people to buy another system if they only want to play a few third party games which are available on Switch anyway. It's not like these games are terrible. The Switch is a full gen behind the competition, so if these people have no interest in XB/PS/PC gaming, are they really losing out? Yeah, it's not the "best" experience, but it's either this experience (which is largely in-line or better than the previous gen) or no experience, and many people choose the former.
Maybe Nintendo gamers are willing to pay more, maybe companies exploit that fact, but I don't see the problem. The wishlist exists, discounts are commonplace. People can vote with their wallets. All the big Capcom / Square / Bethesda games get regular discounts on the e-shop. I haven't bought anything from those companies (digital at least) at full price simply because they are overpriced. More than happy to when a sale comes along though. It's not ideal and you raise valid points, but I think your view that people shouldn't play these games simply because a "superior version" exists pr they're too expensive kind of misses the point. I can't speak for people who pay full price for ports or re-releases, but I don't do it and would advise others to do the same. You don't have to buy a game on day 1. This really isn't hard.
I have a PC and will probably buy Doom Eternal there, but my PC gets played way less than my Switch. If a company puts in the effort to make a good Switch port that runs well (stable framerate, 30fps or otherwise), makes good use of the hardware and is priced competitively (Metro Redux for example), I'll consider getting it on Switch because I know I'll eventually play it to completion and get a good time out of it. I don't need to go on YouTube and have something akin to Jim Bowen tell me "Let's have a look at what you couldda won!" when seeing Doom Eternal run at 4K/60 . If I ignore the other versions, is it still possible to enjoy the game on Switch? Am I missing out on what I don't know / care about? There are only so many hours in the day.
These people are constantly port begging and dreaming of thirdparty games on there Nintendo console, thats why every old game announced they are willing to pay 50$ when you can get it for 10-20$ on other consoles, you can't say they aren't interested XB/PS/PC when they get hard ons for every old thirdparty game announced. it's just simple brand loyalty. I was the same way but grew out of it eventually.