I agree with rainwarrior, at least with regards to nesdev stuff. I haven't seen this many projects (and full-on completed games, including many on cart) in a very, very long time. I can't speak for others, but for me, it's delightful -- just like in my youth with published games, there are some titles that interest me and others which don't. It's almost like a renewed renaissance, and I think that's awesome.
snesdev is a different thing, but I can think of at least 4 separate projects going on (purely based on the subboard here). And to be fair, I honestly haven't seen any snesdev stuff in over 15 years. There's a random thing here and there (like a buddy of mine who made some SNES Christmas demos), but games, nope.
If you want people to "do more" with these systems, the limiting factors tend to be:
1) Level of interest (i.e. get some advocacy efforts going and get new developers interested),
2) Complications from tools (let's just get this out in the open: most people I've seen doing actual gamedev are making their own tools, and many of them are made for them alone); complications means "end users" who might not have familiarity with the innards see the tools and go "what the hell is this?" -- heck, even I do that every time I see some new "NES blah blah tool" come out) -- many of the existing tools we have are neglected or bugged (ex. YY-CHR has several versions, the latest I think of which is busted, and knowing this becomes tribal knowledge),
3) Complications from understanding the systems. I don't want to expand on this because I could write a bloody book on the subject. But when we see new folks on the forum show up wanting to learn how to make things on the NES or SNES, they really have no idea where to even begin. For the NES, Nerdy Nights is the usual go-to; for the SNES it's usually bazz's pages on the wiki. The problem is that writing these guides and walk-throughs in a coherent manner is
massively time-consuming (as someone who wrote documentation for both systems, let me tell you, the way you write/depict something so that it's absorbed better is skill that many lack (I even put myself in this category)). I see a lot of talk/want but not a lot of "do". And I don't do it because I think after 2-3 days of doing it, I'd wake up one morning and say "I'm burnt out from this". Writing documentation/guides is gruelling at times -- and it's not just about writing, it's about editing, too.
If the concerns are with regards to emulators, I'd also beg to differ. There is at least one from-the-ground-up SNES emulator being developed, higan still gets attention, and SNES9x is still getting attention (yes really). On the NES front,
this is pretty disgusting.
If the concerns are with emulation and "new discoveries" hardware or behaviour-wise, I think that's understandably slowed down. There's only so much you can figure out about a system to the point where most everything works. The NES stuff seems to be now mainly focused on figuring out wonky pirate cart mappers, while the SNES stuff seems to be focusing on the unreleased/prototype CD system (though I really don't see the point in bothering with it but that's just one man's opinion); byuu has already stated that there are always behavioural quirks in the console that surprise him when he discovers them).
But in general, when I see someone advocating "more XYZdev needed", I have to ask if that's healthy. More is not always better. Same goes for forum posts/subjects, etc.. TL;DR (and again, opinion): it shouldn't be about quantity, it should be about quality.
If it's all about concerns over boredom and lack-of interest, then I'll point out (what I consider to be) the obvious: you folks do realise you're getting older, right? For example I turn 40 next month. As a teenager and young adult I had a lot of energy and spunk and desire to do things. Once the realities (and pursuits) of life, work, survival, money, happiness, etc. kick in, you find your energy levels lower than when you were younger. The adage "you're only as old as you feel" is true, but I feel 80 (10 years ago I felt 60, 20 years ago I felt 40).