One benefit of developing games for these old systems is that they are not moving targets. For hobby programming, you probably don't want to keep testing and recompiling old stuff to keep up with OS updates.
Even better, you'll have a small army of emulator developers making sure your games will work forever on every new platform. That includes browsers, since there are Javascript emulators for many systems. If your games are particularly tricky to emulate, that's no problem. They will probably be added to everyone's test suites.
https://www.thenew8bitheroes.com/
Games that may be created with it (the NESMaker site links to it, but it's not clear if all games were made with it or not):
> My kids helped design some of the characters, and they love to play it together, which makes it a lot of fun as a family.
> My family (my wife and 4 kids) loves hanging out with neighbors at Morrissey Park in Champaign. Champaign has great parks, and we’re fortunate enough to have a neighborhood community that regularly gets together at the park in the evenings. I also volunteer with my local church and am learning to ride the unicycle.
Dude has been winning at life nonstop.
Eg unicycles are really cheap, and it took me a few idle afternoons (about twenty years ago) to get going on the unicycle. Mind you, I didn't learn any tricks, just how to go forward and how to get on without holding onto anything.
Getting a spouse and 4 kids is a bit more involved, but doable for most people with a bit of dedication.
Raising 4 kids without community support is extremely challenging - the church involvement here is more crucial than you think
Also, I believe Atari carts could be written with standard off the shelf EEPROM hardware. My dad told stories of trading floppy disks full of ROM dumps through the inner office mail system with work friends, and then burning the them to carts.
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.
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.