This is coming from yet another non-programmer type-but is only what I recall from numerous Amiga gaming magazine interviews.
I seem to remember the main complaints from programmers in the early years of the Amiga claiming that if the games were written to be OS-compliant they would've been too slow.
Akira was also right about Hard drives being a luxury item not being in regular use either. I seem to recall though that following development of Kickstart/WB2.x Amigas Commodore "forced" all the developers to start writing OS compliant software.
I'm not sure of the exact reasons but I think it had something to do with the older titles not working on later Amigas (Using the ECS & AGA chipsets)-I'm sure the programmers out there would know what the CBM issues were.