Passed away? Not really. Changed names (DMA Design), bought by other companies, moved to other systems, yes.

Also AmigaOS is still being developed and version 4.1 was released this year (read review). Unofrtunately it's still tied to PowerPC architechture but that may (hopefully) change someday.
However it's probably true that almost all of the Amiga game developers have folded and it may be difficult to trace the copyright holders down, not to mention the improbability of any of the copyright holders still having the games after all these years (or them working if they have them).

There's also AROS, which is based on AmigaOS, but also works on x86 architectures (a live CD is available, booting AROS on your PC)

Having someone at GOG spending days on the phone trying to track down a copyright is money being spent. Easier to spend the same money going to an Infogrames or someone and negotiating for a dozen titles in one go allowing for 6+ weeks of releases for GOG and a good income stream.
I think it's easy to forget that GOG is still just starting up and has to generate income. The fact that Fallout 1 and 2 have stayed at number 1 in their charts show how little other title sales are. I would think that the time GOG has the No.1 selling game changing occasionally is when they have made it enough to go after Amiga titles! :)

I'd love to have a real true blue Amiga Forever all-in-one solution for the very few games that I would want to play that were far superior on the Amiga (or exclusive to the Amiga) like the Cinemaware titles (Wings, The Three Stooges, Defender of the Crown, etc.) since Cinemaware is still around.
BJ

If you go back far enough, you will start comparing Commodore64 games with PC versions ;)

Although music is naturally always superior on Commodore64 versions, most of the time PC versions featured better graphics (even when using lesser colors).

Sorry didn't realize. :)