One was born as a MIDI sequencer with added audio, the other Audio with very little MIDI.

That pretty much boils it right down. I would only note that development of SVP audio software was begun along with the Acadia audio engine. Implementation was waiting only for Mac hardware and HDD capacity to advance enough to use it.
BTW…This was a time when Opcode and Digidesign were located literally across the street from each other in Palo Alto. With Opcode having started with MIDI and Digi with audio, they had a very friendly relationship then. I don't know who was primarily responsible for writing Acadia, but I would bet if you were to successfully decompile Acadia and DAE, you would find a LOT if very similar coding.

Quote from: smilesdavis on Today at 08:21:52 AM
studio vision used pro tools hardware before there was pro tools afaik

By the time of SVP 4, there was extensive compatibility with PT I and II, III/24 and even back to Session 8 and SoundTools. SVP was capable of using DAE or Acadia at any time. That was handy because you could get around Mac hardware limitations, use TDM plugins and import/export PT session files with ease. Exactly where that was intended to go only Dave Oppenheimer and Doug Wyatt know, but it went down the pooper when Avid took over and Gibson blew Opcode up.