it has been a regular conversation in the BTT forum lately and i see no need to worry about it as well, because even if those numbers of bitcoin are sold, more people will buy and stack in there wallet and Hodl for a longer period of time , and will definitely make fortune out of it because they will have created scarcity. i know many people will regret a lot as time goes on they will know the implication of what they have done. because many people with the intention of buying nd holding may have bought tones of it an stack like microstrategy.
Your speculations are just speculations and nothing is definite/guaranteed when it comes to this extremely volatile cryptocurrency market which is why it's totally understandable as to why so many investors dump their stashes on a regular basis.
Some will regret while some won't which is why generalising and saying that everyone will regret is just silly and dumb. Think.