Sound Blasters also had a digital channel, later two for stereo. And the Ultrasound was able to play any digital sounds on its 32 hardware channels (14 at CD quality), not just a MIDI preset bank. Sound Blaster AWE cards took wavetable synthesis further by supporting soundfonts (GUS's .PAT patch format is simpler and closer to to Fasttracker II .XI instruments).
But generally you're right, that's about how it was for consumer hardware before. And you shouldn't forget the other, competing or just different machines of each era. It's interesting stuff.
Nowadays it isn't about sound cards, it's about software. When the computers themselves became powerful enough to handle sound processing while still being able to handle game graphics or application multitasking, sound hardware became less important. (And interestingly, at about the same time they were starting to outsource graphics to so called 3D accelerator display daughter boards. Later the functionality was integrated with the actual graphics adapter eventually making it one of the top-3 most important components when talking about PC performance.)
Of course hardware still matters to prosumers and musicians but keeping in canon with the thread topic, the demoscene and tracking began on consumer hardware, the most widespread machine automatically having the largest potential reserve of sceners around.