I am re-reading for at least the third time, a book not written directly or specifically about trading but that absolutely applies "Against The Gods - The Remarkable Story of Risk" where in it the author in referencing something called The Petersburg Paradox (google it) talks about the "Nifty Fifty" high growth stocks in the late 60's/early 70's and how hyped these stocks got. A couple of examples - Polaroid 96 times earnings, McDonald's 80 times, and a company called International Flavors and Fragrances 73 times, which had $138 million in sales compared to U.S. Steel with a much lower P/E but $5 billion in sales. Same shit different day generation or two. Never ends well .... eventually.
We knew they were coming, including the one this March after ATH again and again. We also told ourselves as soon as we could detect a crash we got out. I was never able to get the hell out when the crashes came including March 2020. We are reaching ATH again and again... I got to learn how to trade vol instead of keep betting on this aging bull.
For those who are too lazy to google the general idea is that a $1 initial pot and a fair coin, you get 2x of previous pot every time the coin lands heads. So if you throw forever your expected value is infinity (i.e. p=1/2 * 2 + p=1/4 * 4 + p=1/6 * 8 ...) but if you are playing against a casino with a finite capital the expected values are pretty tame and flattens out rather quickly.
Probably many did. How long did they stay short? Who knows. Just like I doubt, other than Bezos and a couple of other insiders, many are still holding from IPO many years ago - or actually in their case, pre-IPO.