Apple switched from Motorola 68k to PowerPC, too, and Sun switched from 68k to SPARC. The Amiga, NeXT, early Palm devices, and the ST were also using members of the 68k family. That's an ISA born in 1979 and largely replacing (and inspired by) the 6800 (1974) which had a 16-bit address bus and 8-bit memory bus and its (binary incompatible but with the same assembly language) little brother the 6809 (1978). The Tandy Color Computer and the Dragon were notable 6809 systems.
That, of course, is just with the Mac since Apple previously used variants of the MOS 6502 (1975 and allegedly an illicit clone of the MC6800). Apple, Atari, Acorn, Commodore (the owner of MOS for several years), BBC, Oric, and Nintendo used it in multiple systems each. Apple, Acorn, and Nintendo built additional systems on its updated sibling the WDC65816 series (1983).
The the 6800/6809/Hitachi 6300/68k/Dragonball/Coldfire dynasty and the bastard MOS6502/WDC65816 families were collectively basically the ARM of their day in a way. Everyone targeting low priced or power-sipping was building platforms around them at one time or another. Acorn went from a customer to a major competitor and successor.
It should be noted that the PowerPC and the whole POWER ISA multi-platform family was largely inspired by Apple in the first place. They were talking to IBM about a new platform and invited Motorola to the talks as their long-time processor provider. They formed the "AIM Alliance" that eventually morphed into the POWER Foundation and OpenPOWER initiatives. I can't really speak to how much of POWER ISA is inspired by Motorola's own "RISC" processor, the 88000 series.
