You have a point but there are several factors that in my opinion will eventually prove fatal to Nintendo's console business down the line :
- the lack of third-party support has been an ongoing issue for them for decades, but now with the consoles & games producing costs increasing exponentially, they'll end up not being able to support their own consoles. Look at the Switch library, it's mostly made of ports, cheap remakes and reissues, often sold at full price. What are they gonna do if they release another console in the next few years ? Re-release all those games again ? The trick worked on the Switch because few people played the Wii U games since it flopped so hard, but I don't think people are gonna buy another console to be able to buy the same games again.
- It also means that if they go on making consoles, Nintendo will have to keep cutting costs as much as they possibly can, thus widening their technology gap with Sony & Microsoft more and more. At some point Nintendo will get pushed more and more into niche markets because of that.
- For the last decade or so, Nintendo has been struggling a lot to keep the same level in quality in their games as the one they were once renowned for. So far they have been able to rest on their laurels because of their reputation and blind worship of many Nintendo fans, but if you exercice some critical thinking it's obvious they're on downhill path. I'm not saying they're releasing awful games, but it's just not at the same level as before. As far as remakes go, just compare the GBA era and the Switch era, and you'll see there was a time Nintendo put a lot more care and generosity in remakes. The point is if that trend goes on, the Nintendo brand will end up dinwdling in the next 10 or 15 years, which will obviously hurt their console business.
An additional point I would like to make is that Nintendo has already partially abandoned the console market : there's a reason Nintendo created the Switch, which doubles as a handheld and a console. It was a brilliant idea designed to save Nintendo the cost of producing and supporting two systems simultaneously. It allowed them to abandon the 3DS and focus on one sole system. They've been struggling with those issues for years, it's not anything new. It's also one of the reasons why they've been diversifying their activities lately, with the Nintendo park and Mario movie etc... They're not stupid, they know they need to find other ways to make money.