what killed it? simply commodore dying helped it alot , though its not dead yet but you all know what i mean.
anyway people belived (majority) that amiga's didnt have soundcards , so musicians left.
people didnt see why they should upgrade , so they left and bought a pc (weird eh?)
people wanted 3d games , and amiga was pretty fast saying it was impossible , though if u look at other consoles that was living after commodore died...well its very ironical.
anyway publishers and developers noticed the non stabiity in commodore so they escaped before it would hurt them , sierra,lucas,dma (though they returned a whie later to do lemmings 3) , and most of all , pc outsold amiga games and such in the end, yes its another puzzle but it has alot to do with pcdrom and beeing before the burner times.
now (even with the huge pc market , pc have more problems keeping it stable than commodore had back in lets say 90-92)
and as a last thing , amiga was the bedroom coders dream , but from 93 and up developers and game companies etc hunted everyone down and put them in a job, and as every greedy person, amiga wasnt up for it at that time or later for that matter so they moved to consoles/pc.
but as a good thing, people are returning now ..
people thinks of amiga as part of their life and thats good, i know of a lot of pc people who never felt such a way for their pc..
anyway the bigest problem for amiga users in the past was, people didnt upgrade .. publishers didnt belive in developing for lets say 2mbchip + 2mb fast (which would make the mast twice as fast ) , unlike on pc where games and progs force you to upgrade...amiga did it the otherway around.
and lets face it, we use 12 year old machines (most of us) and try dooing that with a pc (which back then costed 4 times as much compared to an a1200).
too powerfull and developers not wanting to make gamers/users to expand/upgrade their hw killed the amiga , or the userbase anyway.
cheers