I think you nailed it, and that's why vantage points matter. Sitting from a VC's vantage point, it seems like every successful founder who comes through the door to pitch you has a deep sense of purpose.

The reality is that by the time a founder has even entered the door of a VC, the persuasion is perfected to an incredibly obsessive level by necessity and through trial and error. It's to a point where even the founder starts seeing their own revisionist history as actual history...because there's really no other option. There's nothing wrong with this - it's extremely rational and a normal consequence of the environment. When you pitch that often and craft your story that often of course you will buy into it more and more over time regardless of the extent to which you bought into it initially.

It's really the attempt to understand this phenomenon from the wrong vantage point that is flawed - as you pointed out.