A PDP-8 can be implemented in fewer transistors (original DEC wiring diagrams are on bitsavers, and github has source for several clones in Verilog), and DEC already shipped a moderately full software suite for it.
I mean it was built out of off the shelf cheaply (relatively) available TTL components and no real RF shielding (something variants in the US had to fix to comply with the FCC rules of the time).
It's astounding it was a commercial success but it cost 80 quid (as a kit, 100 pre-built) at a time when others where 3-4 to 10 times as expensive (average wage back then was around 110 per week).
In a very real sense it democratised computers to something almost anyone working could afford if they wanted it.
I know if it hadn't of been for the ZX-81/ZX-Spectrum I wouldn't have had a career in software engineering nor a life long love for computers, I was born in '80 to working class parents in the north of England even in 1987 having a computer was considered exotic among my cohort, I didn't see another one outside my family til 1990 (a C64 I lusted after).