Commodore-Amiga was the most incompetent. They had more to work with, and still threw it all away. This is the computer industry. You can't keep selling the same machine with minor improvements for nine years and expect to survive.
I was still a teenager in 1992 and it was obvious to me, even then, that C= was doomed. I couldn't believe their stupidity in releasing the A500 (A1000 in a wedge design and 512K RAM), A500+ (A500 with a new ROM), A600 (A500+ with numeric keypad chopped off), A1200 (020 and AGA but the rest of the machine, including the blitter, sound and virtually everything else was the same as the then-ancient A1000), CD32 (an A1200 with a CD-ROM drive, same crappy 020 and no Fast RAM).
Everything Commodore released since the original A1000 was old before it even hit the shelves. There was nothing original or groundbreaking. They deserved to go bust a lot sooner than they did - they were very lucky to last until 1994.