Aside from lithography there's clever design. I don't think you can quantify that but it's not nothing.
... the rest is history.
Acorn won the bid to make the original BBC home computer, with a 6502-based design.
Acorn later designed their own 32-bit chip, the ARM, to try to leapfrog their competitors who were moving to the 68000 or 386, and later spun off ARM as a separate company.