I think the problem with this generation is that the amount of people buying these peripherals is higher than any other generation. Few people cared their Powerpad didn't translate over to the SNES, because the amount there were "substantial" controller differences. After the original Xbox and the PS2 Dual shock, MS and Sony's controllers have remained pretty much the same. They haven't really added any more buttons.
As far as fightsticks, I have purchased quite a few. I have an HRAP and two dual modded 360 fight sticks as well as a PS3 stick I only use for tournaments. That is quite the investment I'm okay with "giving up" on the new consoles.