MSX Democomp?
Lieves!Tuore is alive as ever at least 
Nyyrikki does occasional Turbo R prods, Traktor has been somewhat active on the MSX2, and then there's Dromedaar Vision, another Finnish MSX1 group. Other than that very sporadic. I don't think there are specific compos, but many parties would surely accept MSX demos in their "oldschool" or "wild" categories, as long as you take the hardware there yourself.
Pouet's list is most likely up to date:
http://www.pouet.net/prodlist.php?platform%5B0%5D=MSX&platfo...
My theory is that the once active Dutch MSX demoscene was verrrrrrrrrrrry oldskool, very much like:
"Hoooo boy, look, a scrolltext and a logo, and the logo even waves 16 pixels horizontally, hoooo boy! And now we can even read one hour of bullshit, and hooo boy, I'm in the greetings! No wait, these are the anti-greetings... ahwell, gonna read it all, hooo boy! Oh look, bouncing sprites... and there... a color cycling fractal!"
And I just estimate that at some point people were out of ideas on the scroll+logo concept. True, there have been a few exceptions (Unknown Reality most notably, although still somewhat post-oldskool), but the biggest stylistic changes are indeed 'foreign', and very much like demos on other systems. Baltak (Traktor), for instance, is everything the MSX 90's didn't have. Another theory would be that somehow most coders shared roughly the same age, and at some point they all went to study and moved to PC's.
I once had some friends over at my places, and they're real C64 nuts. And I showed 'm some oldskool stuff, and they were like: "Wait, what, is this that computer that has more colour choices, a separate video chip with its own memory, and a CPU that's three times faster than our 0.8 MHz CPU?"
One thing that is remarkable for me is that the oldskool MSX demos were never really 'timed' demos with a sense of storyline. As a consequence music was merely a byproduct without real synchronisation. Such demos could run forever unless you hit Escape at some point. On other systems, a demo of 5 minutes has a tune of 5 minutes. Even the classic Source of Power (ANMA), though having multiple parts and multiple stylistic sections in the music as well, wasn't really synchronised. Not at least because you could simply skip to the next part.
In a way, with all these variations of all the countless scroll 'n logo demos, you could say that we have advanced simple effects. While 'newskool' would be more like simple 'lo-fi' versions of advanced effects. Meaning that a 3d tunnel, a plasma etc. could look simple/blocky. Still the idea would be more challenging than a scroll routine and some screen splits and tons of boring texts.
That, in a nutshell is the difference in demos among systems.
And in the 90's even I liked it, that's the weird bit! It's just that I never saw anything other than my MSX, so my reference pool wasn't that big.
Pick one:
- We moved on...
- We are to lazy
- Too busy fighting
- not creative enough
- all of the above
Pretty much the case for any scene anywhere 
But to consider it a bit more seriously, I guess the non-Dutch MSX people largely have some generic PC/Amiga background and the MSX is just one target platform for them.
It's not too late for a revival, is it?
I think that on the demo scene, coding is like a means of self-expression and the machines or "platforms" are seen like a canvas and paint for an artist. But of course, the sense of aesthetics is very different from other art forms. Do something neat in... 4 kilobytes, 1 kilobyte... 256 bytes? Anything goes as long as it somehow tickles the audience.
Who's the first one to make new kinds of visual effects with the GFX9000? It's largely unexplored territory.
