Can't blame ourselves for not taking the opportunity, no one expected Bitcoin would go from $3800 to $16500 in just a few months anyway, just pure regret on not realizing that this would be coming, and now, the price is at $43000, that's quite insane, those who made the huge profit are the real winners here, also, it's just a matter of luck with the numbers and probably a close observation on the price, if I were even trying to make huge profits, I'd still think that the $3800 price would even go lower and try to buy some bitcoins lowe than that, but now all we can do now is pure regret, it is what it is, I guess.
That is because people look at the chart and also see that Bitcoin can go from $1500 to $100 in no time, just as an example. That is why it is true as you say it, nobody can predict it. Bitcoin has had many turn arounds in both directions with full force where sometimes people thought now the time has come it is going to die, or now the time has come it is going to a million.