Also, part of the experimentation of the 80s was that people had money coming out of their ears back then.
This was my thinking, too. A lot of the peripherals for Japanese consoles I've read about remind me of the sorts of things you could get for 8-bit home computers in the US when I was 1st-grade-ish, but taken to the next level in terms of variety. To me, this argues a similar impulse fuelled by more funds. On the other hand, you have things like the Loopy coming out well into the 1990s and I don't think I've ever seen anything quite like that this side of the Pacific. Could be I'm mistaken, but this makes me wonder if it's more than just money that motivated all the accessories & add-ons....
/edited for clarity