When I was in the Australian Defence Force on the 90's and 00's we had a big gender push into many "men only" jobs.
I remember when submarine service opened to women. Flood of applicants initially as expected but then it pretty much dried up. The "hundreds" of women submariners never materialised.
I think aviation is the same. There just aren't the numbers of women interested to make it a 50/50 split. Nothing to do with ability, they probably just want a different career.