You can not compare MAG and WAG.
MAG predominantly relies on the adult strength that boys do not develop until after puberty. There are many skills in biys gymnastics, that you simply can not reach them until the teen years when they are developing those adult muscles.
For girls it is generally the opposite and it’s easier to teach skills prior to puberty, their strength to body ratio is different.
There are so many reasons why girls skew younger in gymnastics.
Starting at the very beginning with your 4-6 year old gymnasts. Girls at this age in general listen better, follow instructions better, can focus on detail, focus for longer etc. they are ready for a structured more technical program earlier.
Boys at this are less inclined to structure, focus, listening, etc, They aren’t ready for a structured class that focuses excessively on technique. They need to run, jump, climb, swing and develop,op their body awareness.
in older children, say around 6-11 for girls, this is the key developmental time, they need to learn more skills, earlier before they go through puberty. This is the ideal time to teach the big tumbling and flipping skills.
Biys at this age, can’t do most of the “big” skills required for their sport. So they are better to work on a modified program that does teach the things they are ready for like tumbling, building flexibility (as this will be harder later) and the fundamentals on each apparatus, to prepare for when they are ready for the big stuff.
So this type of development encourages girls to be pushed through your and boys to wait.
Fro, there girls will go through puberty earlier, and hit peak height earlier. Boys will develop later and tend to have longer international careers.