the variety of soundcards was not really the problem. almost all soundcards weren't able to do hardware mixing at all (GUS and AWE are exceptions) so everything had to be performed in software anyway. When IT filters were introduced (this was very late, 1996 or even 1997 IIRC), the IT format was already quite advanced, but CPUs were still slow, so you had to have a MMX-capable CPU in order to get filters in Impulse Tracker. But seriously, I think it's very blindfold to judge a format by hardware support. I mean, would you as an artist despense with sexy filters just because of the hardware? Especially nowadays, when every IT player (well, except WinAmp -_-) can handle filters?