Old thread, but the OP makes some good points that I can totally agree on.
The fact that it took programmers a year at least to get their head around collision routines that didn't drag down the entire system.
OK, technical reasons play into it, but there are no technical reasons that can't be overcome.
I honestly believe that if the 68k wasn't hyped up so much by game developers, slowdown in SNES games would have never been an issue in the first place. After a few years of the 68k became standardized in the arcade market, programmers lost their ability to work with CPUs that were notably different.