Actually two things.. sound on the Atari was actually crap compared to the Amiga's own sound capabilities (after I hooked my first A500 thru a decent Amp and kicked off Falcon, many ST friends were extremely jealous).
Secondly the midi port on the ST was also not that great. All a midi port is, is a serial port with a couple of ICs added to it, so it was no wonder that a few years later decent enough midi adapters were cheaply available for the Amiga.
In regard to the "famous" Atari music package. Yes it was the dogs gonnads, but by 1993 was superceded by a PC version, which pretty much left the Falcon (with it's famed DSP sound system) dead in the water.
Also by that time, Bar & Pipes was a far more superior package, which never got the attention it deserved from the music industry (they were also convinced by the midi propeganda that the Atari was the only machine for music, and after their software was moved to the PC, they also moved on).
