They didn't respect their product, and they didn't respect their customers. That's why they went bankrupt.
QFT.
The company was all over the place. The Plus4 and 16 were barking when they had a winning C64 design and they weren't as good. Even so, the C64 was a reliable money earner through the 80s.
I am sure that C= thought the A600 would be the C64 for the 90s, and that people would probably be buying them to connect to their TVs for a decade.
The A1200 and A4000 were two years too late. Even though an earlier release would have made the machines more expensive to buy, they would have been obvious upgrades for potential and current A500 owners - the A1200 especially at a couple of hundred dollars more.
E.g., 1990: £399 A500 (68k, 1MB), £599 "A1200" (A500 casing, '020 CPU, 2MB) - probably called the A700 or something.
And that's before we talk about the chipset debacle, and the issues with corruption that have been bought up in this thread.
