Hmmm, so bitcoin run-up is rational? At market tops price will often pop. Is this rational where price leaps then crashes? No, I am not convinced of the theory market is always rational. Markets driven by algos may be considered rational in terms of algo driven but they are not considered rational in terms of value. It is possible to trade irrational markets using rational trading experience. All kinda twists and turns in this.
To bring up Keynes again, "The market can stay irrational longer than you can stay solvent." Knowing that a bubble is irrational is a very different thing from being able to reliably profit from that knowledge. The number of investors who have put their money where their mouth is and correctly predicted multiple crashes without getting wiped out being short in the interim is vanishingly small for a reason.
whose reasoning? yours? those who are buying bitcoin now have their reasons, and their logic you may not agree with that reason and that logic but it's there and as i said to the OP earlier: your rationalizations, while seemed logical, is simply revamping the facts to the version that does not contradict your beliefs
I think the best one can do is take small bites. Impossible to know the full extent of a trend beforehand, therefore small nibbles along the way, depending on your trading time frames.