Boku No hero Academia I: because it deserves a thread.

[John Cribati]

Hah.. i think you forgot a 0 on that estimate. That there are someone like Deku shows that it also runs the other way, that Quirks vanishes again.
And we have not seen any noticeable difference in power between the generations.

Also, 3 to 4 generations means there is an extremely blatant leap of power between each generation, but since its a theory that clearly not to many know about, instead of an accepted fact. Then the power leap clearly cant be that obvious.

Well for one, cases where two Quirked parents produce a Quirkless child are super rare, and for 2 Quirklessness is clearly on a decline, given it was already uncommon in All Might's day and even rarer in the current generation.

Besides, I'm more talking about the mixing of powers aspect of it. Unless everyone immediately segregates by specific categories, Quirks are already mixing by the first generation post-quirks. I'd imagine most Quirk Marriages are either expected to result in a better version of their own power (e.g. two weak telekinetics hoping for a stronger kid) or more variety in ability (e.g. Endeavor breeding for IVs I. Canon), so maybe it doesn't bring ot a whole generation closer, but normally you'd basically the children of generation n will have the potential of 2^n quirks.