I'd criticize the graph. There's no way males' social value has exactly the same amount of variance as females' value. Imagine a 22 year old Stanford Law student. Sure, he hasn't made any money yet, but an 18 year old girl will know that this guy is going to be rich. He'll have no problem at all sleeping with girls in the 18-22 bracket. In the US at least, that guy will have a much harder time with many 18-22 year olds when he is 36 due to the age gap. He'll only be doing better if he was aspie at 22 and then learned game, or really became a millionare. But the game he probably learned by 28, and was probably already pulling down $160k by the age of 26. Thus, I don't see a case for a male ascent from 30 to 36 the same as the slope of the female descent from 25 to 30...
The factor that does increase from the age of 30 to 35 is the potential age gap with girls. Even once you turn 45, you'll find some 20 year olds who will sleep with you, but you won't pull at that age bracket in the US like you would at the age of 29. However, at 29 you can only marry a girl 11 years younger than you, whereas at 45 you can marry a girl who will only be 33 when you are 60. Because of this, the later 30s might be optimal for marriage, but unlikely your SMV will be dramatically higher by then.
The factor that does increase from the age of 30 to 35 is the potential age gap with girls. Even once you turn 45, you'll find some 20 year olds who will sleep with you, but you won't pull at that age bracket in the US like you would at the age of 29. However, at 29 you can only marry a girl 11 years younger than you, whereas at 45 you can marry a girl who will only be 33 when you are 60. Because of this, the later 30s might be optimal for marriage, but unlikely your SMV will be dramatically higher by then.