The reality is that they would not have been able to hold for so long even if they bought 10 years ago. Very few have the patience to wait till 100x or more. Most of the investors will be sold at the idea of 2x or 3x itself. Some of the people that were able to hold for so long were those who had invested and then completely forgot about it. There is one more category of people who had complete trust on BTC and thus they stick with it for years.
Right, 99% of the people that would have invested in Bitcoin back 10 years ago would have sold before it even got to $1k, and those that were still trying to figure out how they saved their PKs/PWs would certainly be amongst the few that believed in trying out this new thing and keep holding for much longer. Those were the early stage of Bitcoin and lots of investors weren't 100% sure of what they were investing in.