Personally, I tend to look out more the indie Mega Drive releases but I really love the fact that people are still developing for these platforms.
https://www.youtube.com/watch?v=gWVmPtr9O0g
That system has no business producing any kind of 3D graphics but they did it anyway.
The Master System had stereoscopic 3D games too. As did the Famicom. I have both of their respective 3D addons too. Missile Defence in 3D is pretty cool. Hard to believe it’s 30+ year old tech.
I think maybe I got my wires crossed with Virtua Fighter 2, which did see a Mega Drive release but as a 2D fighter (the VSP port being cancelled - presumably because of the cost of the VSP).
It's true that it's not a huge market, but it's an interesting one. First, most of us involved are making these games because the old platforms themselves are what's interesting, so a modern engine just isn't any fun. So we're not remotely in tune with what's practical.
But beyond that, the community of players and buyers in this community is very engaged and supportive, which makes it very different from other indie dev. Indie games for a lot of other platforms have a long tail... if you get noticed, you'll make good money. If not, you'll make almost nothing and it will be crickets. In NES development, you're guaranteed to have a number of people that are engaging with you and supporting your work. It's still rare to make enough money to really make it a well-paying job, but it's a lot of fun as a money-making hobby.