I think it’s likely attributable to financial returns of angels.

One of my business school professors was a prolific angel investor. I asked him about his returns and he laughed. He said it wasn’t about the returns - by the time he cashed out, he was so diluted (or enough failed) that the ROI was far less than an index fund.

What it did give him was social capital - to say he was an angel in a famous unicorn was immensely valuable to him.

Unless you’re already rich, social capital doesn’t pay the bills.