1. No visionary management. Imagine what the company would have been like with the tyrannical perfectionist and visionary Steve Jobs. Actually, anyone who would have focused on bringing in the very best at a reasonable cost. I mean they had their own die-factory for goodness sake, they were not even that dependent on using others technology. The legendary bumblings of the most terrible management team and borad in the history of computing. They should make a movie about this or press charges.
2. Product placement and features. Example. The A600 is a great machine when the expectations are properly set as being a sub-A500 machine, but as a successor, it was a joke. The A3000 was great and should have evolved and almost did with the additional video card for UNIX, but again no vision. The A3000/UX could have been a game changer.
Amiga always had the engineering brilliance, the technical genius, but failed to put them together in a cohesive strategical and committed way.
3. No commitment to products. These half-baked launches, aborted programs, poor roadmap for products. Someone was just trying to turn a damn buck.