If we knew what the future would hold, perhaps many people would be more greedy. I once sold bitcoin at a price of nearly $400, but to say it was a complete mistake I don't think so, because I'm still here and my confidence in the opportunity that bitcoin brings is growing.
The story that OP mentioned here is probably the common psychology of many people, they only feel comfortable when the investment profits immediately, or the loss is not too much. I feel like it's more of a short-term trend than a long enough process to see fluctuations. Ask people who have invested for over 5 years if they've ever seen their investment decrease by 90% but still keep it then receive a large profit. Not everyone has the same opinion, as well as approaches to investing, so take every story as a lesson to look back at what your own investment is getting, it's not necessary to always say in terms of monetary profit, but also things like knowledge accumulated and applied back to that field.
Individuals frequently overlook the long-term effects of investment because they are engrossed in the short-term trends and feelings involved. Investing demands perseverance and patience; it's a marathon, not a sprint. A 90% dip can be demoralizing, but persistence can pay off with enormous advantages for those who persevere. You also correctly point out that investing is about more than simply making money—it's also about the knowledge and experience you pick up along every step of the way. That's a really crucial thing to remember, in my opinion, especially for people who are new to investing.
I've also had similar experience as the OP, some years back, I decided to diversify my investment since Bitcoin trend wasn't encouraging, and I've till today regretted that decision.