“Mistake” is very clearly referring to the topic of retaining equity, with the assumption that more is better. I’m not criticizing the founder in general; e. g. Microsoft has made many mistakes in its history, but clearly Gates is immensely successful.

Obviously if giving up 99% is what enabled you to get to the 100m, then sure, it could be considered worth it. But if we look at virtually any startup with a high valuation, the founders always manage to maintain more than 1%.