I think that's a really good point. Also some older gamers aren't exactly unbiased sources either, they could be relying on memory from over 20 years previously, and might have only really played their handful of favourites recently. I probably played 40 or so SNES/Megadrive games back in the day, but only a dozen of them have I replayed within the last decade. That's a shortlist of favourites solidified in my memory quite a while ago, not really a list of exactly what's any good now. I'm not sure I'd necessarily agree with my 16-year-old self twenty years later!I'd say Super Metroid over Yoshi's Island, but this list looks pretty much in line for what I'd guess.
I think, as you get further back, the list tends to be more and more canonized, as those people who didn't readily grow up in the era and are interested in gaming history are more likely to play those 'universal acclaim' games and not so much something more obscure (but equally fun) like Lufia 2.
I suppose the number of voters works to round out poor individual memories.
As an aside, the lack of some SNES titles having been released in the EU (FFVI, Chrono Trigger) might mildly drop their positions slightly, you might see Secret of Mana instead on those votes.