i dont believe that anybody outside of Commodore actually killed the amiga(apart from perhaps microsoft, ibm and apple...)
I believe that what killed commodore was one braindead business decision after another. Like launching the A500+, then less than a year later canning it and replacing it with the A600.
The companies you mention: as at 1994, when CBM imploded, Apple was a competitor, but I doubt they had the power to kill the amiga. Microsoft was taking over on the x86 part of the industry, but based on their relationship to Apple (ie it's their "proof" that they're not a monopoly), I don't think it would've done it. I think it's even possible that they would've ported Office to the Amiga, just to keep the DOJ off their backs. IBM's attitude toward the Amiga back then was what it is now towards Apple (if you ignore their CPU division) - they don't see themselves as being in the same market segment.
