And frankly by the late 80s the 680000 architecture itself had hit a dead end performance wise. Maybe Motorola could have pulled off what Intel did with Pentium, paper over the aging CISC with RISC internals, but instead we got PowerPC.
I'm not sure if you ever used a PowerPC Mac when they were a mix of emulated 68k and PowerPC, but they were notoriously unstable. The mix of a lack of memory protection and emulated CPU instructions would have been the same for the Amiga and Atari ST whose OSs also lacked memory protection and safety features of more modern operating systems.
I have an Atari Falcon 030, Atari's last and best machine. It is a really really nice machine. But it was hobbled by poor software support -- it's only now that hackers are discovering what they can do with the combination of the 68030 and the Motorola 56k DSP in it (Example: Quake 3 has been ported/rewritten recently for it, using the 56k for 3d acceleration.)
I used to wonder what the world would have been like if the 68000 systems won out. But now we're seeing a world where the ARM belatedly wins out, which is kind of neat, tho ARM is arguably now as "evil" as Intel :-)
What is an interesting mental exercise is imagining what would have happened if the 6502 or 6809 architectures had expanded and done well. Those architectures had insanely fast interrupt processing and very fast (single CPU cycle) memory access. Some really neat machines could have been made if they'd continued to advance them, gotten past the 64k memory address limit and into high clock rates. Western Design stopped at the 65c816, a 16-bit variant of the 6502. Something faster and funner than the Amiga could have been built with a 32-bit 6502 descendant and chipsets similar to what was in the Amiga. That would have been really neat.