I think we've all thought about alternate history before but here's my take: by '84 commodore/mostec should have had a 12mhz 16bit 6502. the c128 should have had that in '85 with the ocs chipset, and an enhanced geos os. by '90 a 32bit 20mhz 6502 with ecs... etc. etc.
by '85 most of the 8-bit producers wanted to go 16 but mostec had nothing for them so they went to the 68000. the 68000 was a great chip but it was quite a few years old in '85. all us c64, atari 800, and even apple II fans had to "make the switch". the apple IIgs was hardly advertised at all and still managed to outsell the toy mac untill apple ramped up mac ads and bury the gs.
pc people never had to "make the switch" and could get hardware from multiple sources. that's why we have core-blahdeeblah etc today.