Wrong. You're talking about an Amiga that existed in *theory*. In practice, they were horribly expensive, and you could get a higher spec PC for less cash than a high spec Amiga.
As mentioned upthread, there were plenty of other expansion possibilities that were cheaper, and given that almost everyone I know expanded their 1200's, there was obviously a market for this, that game developers could have aimed at.
Wrong. Doom in itself didn't kill the Amiga, but the technology it used did. Playfields, copper and sprites was hot 1985, but 100% useless when texture mapped 3D games became mainstream.
You really believe this was a bigger factor than the fact that there were no new amiga's to buy all of a sudden due to commodore not being around?
This is going back to the same notion that the only amiga that ever existed was a base, unexpanded machine. Had commodore been around past 94, they'd have updated the graphics, as they were in the process of, just like everyone else did.
Nobody considers nintendo a failure because the NES couldn't run Doom.
Nobody considers the PC a failure because a 286 couldn't run Doom.
But everybody considers the Amiga to have failed because the A500 couldn't run Doom.