Same author talks about Angel investors getting screwed by later rounds.

  Here’s an example of a portfolio company that not only converted angel investor ownership to common stock, but also drastically decreased the number of shares.

  I started asking for pro-rata side letters in 2017. But I recently found out (the hard way) that it’s common for follow-on investors to completely disregard any pro-rata rights of angel investors.

https://www.halletecco.com/blog/angel-investing-part-iii#:~:...

Perhaps also relevant:

  Founders, like entry-level workers, are closer to an option than a stock. There's a good chance that the payoff will be negative (in the sense that sometimes a company going to zero is a significant time-consuming process to investors). Someone who continuously buys out-of-the-money options will bleed money over time,

From: https://capitalgains.thediff.co/p/the-favor-trading-economy