That's true, but all that could have been added to Coherent. I'm stressing Coherent here because it was the cheapest Unix clone available back then.
> All the UNIX ports, including the follow up AMIX, were a shadow of the multimedia capabilities of AmigaOS.
That's a hardware enablement issue. The biggest drawback of Coherent (and most Unixes back then) was that it couldn't run from a floppy, so, the minimum viable Amiga would need a hard disk. It could be possible to slim it down, however, or, maybe, just adding a POSIX compatibility layer on top of the AmigaDOS base would suffice. My point is that, if Amiga users had an easier path towards Unixes or if universities got lots of Amigas instead of far fewer Unix workstations (for the same money), we'd have a somewhat different world right now.