The thing I find interesting, and I'd never heard of the C65 either, is that the copyrights are 1990. So, in the midst of attempting to mainstream the Amiga CBM was dumping resources into the next 8-bit machine? Oh my....
Instead of focusing all their folks on pushing forward, CBM was busy reinventing the past.
Hell, apple did the same thing with the 2GS. Atari was slinging out mini 2600's well into the 1990's. Nintendo was selling the NES (not SNES) in the US until 1995.
Fact is, well into the Amiga's life the C64 was still being sold and outselling the former. It was still looked on fondly, and to be quite brutally honest I think a C64-like with a "desktop" OS running at 640x400x256 (which the C65 was capable of) probably would've kept Commodore around longer.
The '65 ran at around half the A1000/2000/500's CPU speed, but had superior graphics, and was just as expandable in the RAM area. I'm quite sure 3rd party addons would have given the '65 the same oomph that the 500 had.