Hi, Author here. Apologies, I should have made it clear that this was intended to be a short list of microprocessors only, mostly to leave room for a follow up on microcontrollers like the 8051. Completely agree that the 8051 deserves a place on any list of important 1970s architectures.

If anyone is interested in the results of the poll which looks like a dead heat between the 6800/9 and Z80, then the winner was Motorola. So I'm now deep in research on the 6800, hopefully to result in a post in the near future.