There’s a relevant point that gets missed in some of these discussions:
The time of greatest MPB damage occurring is not the same thing as the time of the greatest visible evidence of MPB increasing.
Greatest MPB damage occurring is probably in the teens & 20s for most men. I think I read one time that the highest hormone levels relevant to MPB are during 20-35yo, with 25-30yo usually being the peak. But at those young ages, a man’s baseline hair condition was usually still very good to begin with. The visible evidence of the loss might get much more rapid in later decades but that’s a different issue.
In real-world example:
Let’s say a guy loses 40% of all his density in the decade of his 20s, and then he only loses 20% more density during his 30s. So his twenties were clearly THE bad decade for hair loss.
But what’s the visible effects of this?
Suppose he got to 20yo with 90% of all his original density. He goes from 90% all the way to 50% in that decade, but he turns 30 still LOOKING like he’s not having much hair loss at all with still having 50% density.
Now, over the course of his 30s, he only loses half as fast as he did during his 20s. But the difference between 50% and 30% is very obvious when he looks in the mirror.
So if you ask this guy, “when did you lose your hair?” He’s probably gonna tell you that he was doing just fine during his 20s but then it all went really fast during his 30s. But that’s not what really happened at all.