If you look at US multiples (the S&P500) they are now actually around historical average. The rise has been driven by EPS growth. Other assets and global indices have not grown earnings or new industries. Most global innovation, meaning genuine new products, is in tech and healthcare (including meet medtech and bio), two industries were the US leads by far.
Why these hedge funds have underperforming so badly is probably because they think they were smart, and were not. Also, this are not all hedge funds, just some previous leaders who just didn’t have anything sustainable going for them. There are others who have done very well.