Who is that one man that you are talking about though? Well, if you had bought bitcoin when it was around 1$, you are definitely rich by now. Also, there's nothing wrong with people wishing what they could've done in the past, it's called hindsight.
Agreed. At least by looking into the past people can learn some lessons and hopefully will help them be in a better place someday.
For instance, if BTC drops to some unexpected value of say 20K zone then those people who were once wishing they could buy in then will have their chances while others with no wishing at all will wait for lower dips before buying in but there can only be a certain amount of discount.
The point being that if you see a chance grab it because one day it will pay off.