Erasmus-X, I already conceded that the SB Live! has better MIDI capabilities than any Aureal card stock. The thing is, Aureal cards have the option of upgrading to better MIDI via a wavetable daughterboard, and SB Live! don't. The price issue isn't really a factor here because of the fact that the SB Live! doesn't even support it. Beside, with a good daughterboard, the Aureal really does kick the SB Live!'s butt in MIDI, so why shouldn't it cost more? I think its logical and reasonable that if A is better than B, then A should cost more than B, even if A is made up of 2 other separate entities C and D.
As for your last statement, I agree full-heartedly. However, there are still quite a number of MIDI hobbyists and amateurs who don't have wads of cash lying around, that might like the soundcard + daughterboard combo, me being one of them. It just allows for more flexibility.