You and OP make way too much of this. Have you actually read any autobiographies? As with any piece of writing, you have to form your own judgements, but people can't completely fabricate their life stories or delude themselves about the reasons for their success.
Autobiographies I've read, and enjoyed, even though I think the writers are all in different ways dishonest, include Malcolm X (street gangster turned religious leader), Gandhi (moralistic prig with weird sexual perversions), Bertrand Russell (projects saintly calm but had weird bouts of rage) and 50 Cent (claimed he never smoked crack, and it only accidentally ended up in his bloodstream). Still, I believe all four are accurate when describing the reasons for their success.
(For more honest auto-biographies, I'd recommend Ben Franklin, Winston Churchill, and Richard Feynman, off the top of my head).
Either way, no-one writes "I achieved X by doing Y and Z, it was simple", it's more like "I tried to achieve X by doing A, and that went disastrously, then I tried B, and made some progress, then I realised X was a waste of time and went after Y, and noticed most people who wanted Y did Z but that didn't work for them, so I tried doing C, then D, and then E, and that's when things began taking off".