Earlier quoted context omitted.
When Robert Fischer achieved an unprecedented scores in the pretenders matches prior to winning the champion title, I believe that the biggest factor was not the quality of the play of Fischer, but the way he mentally unbalanced and broke his opponents, who absolutely did not give a performance they were capable of.
The unnerving, unbalancing effect Fischer had in the 1971 Candidate's tournament was absolutely due to his play. He put up immense resistance against lines prepared by teams of Soviet GMs (example here https://www.youtube.com/watch?v=X8-90cPf61M ), which was the sort of thing that broke their nerve. He was not intimidating or manipulating his opponents outside of the board; if there were any outside-chess forces at p…
They absolutely were blundering much more than they did vs other opponents, showing a far lower quality off play than usual. Also I believe you didn't read much about his championship match. Remember how the games were moved to a different room, and why?