I was disappointed with the Rise and Fall of Commodore book coverage of the Amiga, it felt tacked on at the end a bit and didn't go into enough detail.
From my point of view, I needed to switch to the PC because of going to uni and having course work to do that required DOS/Windows.
But in a more general way, at that time the PC finally got a GUI (poor but if you'd never seem anything else it was ok) thanks to Windows, and not long afterwards, the face of gaming changed with Wolfenstein and then Doom. At that point, 2D graphics hardware became much less important, and the CPU in the PC started to get ahead of other hardware.
It would have taken a very determined Commodore to rise up to this challenge, and there might have been a few steps in that direction, but the management either weren't committed enough, or didn't have the money to do it.
Not saying that's how it was, but that's how I saw it anyway.