I think about a great opportunity people had miss when Bitcoin was still in a lower price, imagine how many people Bitcoin would have made a millionaire, though by then most people were a bit skeptical about the growth of Bitcoin, if it has a good potential or save to invest.
At that time when bitcoin was close to three digit price in USD, people were buying but the exposure of bitcoin to the global population was limited and hence there were smaller booms in price. With gradual mainstream appearances of bitcoin we have seen the bigger price ranges to be achieved, which adds up.
Although the price going up made a lot of people regret their mistake of not buying at the low, not every country is lenient about crypto and if you live in one such, then you have no other option.
Again it is also true that someone who bought at say 500$/BTC, would defenitely sell at 10k$ without looking back. But if they bought back at lower price, then only they might have held to sell again at 20k$. What I mean is that many people have completely exit the market at much lower highs.