People who commit fraud at that scale are not a dime a dozen.
If you read Bad Blood there are quotes from her wealthy investors saying things like "well, her great-grandfather was a famous surgeon so medicine runs in her family!" as part of their decision to invest in her.
I grew up with the mindset being told if things were too good to be true they probably were and to expect failure and be pleasantly surprised if things worked out. This is practical advice for many lower to middle class individuals, but it can also hold you back because you stop looking for genuine opportunities. Better advice would be to do your due diligence.
With Holmes, and hindsight is always 20/20, it should have been obvious that she was full of shit. As you say, I have met dozens of people, men and women, like her, that just lie reflexively and I have learned to spot them from a mile away and avoid them at all costs. If you catch someone lying or exaggerating something inconsequential, and by that, I mean it really does not in any way help them or get them out of trouble, it is easy to brush it off as a white lie, but it is the people who will lie for no reason at all who are the most dangerous because you can be assured that they will lie when they do have a reason.
Holmes' mistake was to massively overdo the "fake it til you make it" in a regulated industry where the implications of the lies appal people, as well as to have a product that was never going to work so the lies were more "this car definitely isn't just rolling down the hill" than "the person at the wheel is only for regulatory reasons". If she'd settled for fantasy metrics and self dealing in a real estate play rather than faking medical tests she'd have investors lining up to fund her second venture...
I'm more intrigued by how she managed to keep customers and at least some of her employees believing and how often that mask slipped.
And then an extremely tight circle of people she knew she could manipulate. Liars hate people that see through their lies and get rid of them as soon as possible or otherwise try to ruin them.
I agree with this point. I think that in the investment world, many VCs investing in deep tech are not deeply familiar with the underlying technology. They often say they are betting on the founders, which can inadvertently encourage this behavior, since founders know that their investors are unlikely to scrutinize the technical details too closely.
(Btw, your comment filled me with warmth, thanks. I also recommend Scott Aaronson's "On Self-Delusion and Bounded Rationality" [1].)
[1] https://www.scottaaronson.com/writings/selfdelusion.html