The Atari ST was the logical progression of the Commodore 64, and the Amiga was the logical next Atari 800.

Whatever doomed the Amiga wasn't just Atari's suit, as the Amiga lasted a lot longer than Atari did in the PC business.  What I think really doomed the Amiga was bad business heads.  They didn't really know how to market what they had, or even realize what they had.  Oh well, I still run AmigaOS on my quad-core PC; just for kicks.