[HamiltonJay]

The 6502 and its derivatives drove the home computer market.... yes a few z80 based machines existed, but the vast majority of the early personal computer market were 6502 based.... In fact they still manufacture an ancestor of this chip, it is used extensively to this day in various ways...

http://westerndesigncenter.com/wdc/w65c02s-chip.cfm

[Dr. Sivana]

but the vast majority of the early personal computer market were 6502 based

Besides the Z-80/Z-80A computers mentioned earlier (and omitting the earlier 8080 and 8080A first generation home computers), There were a number of none of the above, some of them selling very well. The TI-99/4A was a good seller, and of course sported TI's own processor (16 bits!)

Apple/Commodore/Atari were a good chunk of the market, but I wouldn't call it vast. More like Chevy vs. Ford vs. Chrysler than Cisco.