I think it’s probably too simplistic to just pin it on the number of applicants and the reason for that number being that they’ve not been motivated to apply.
But I don’t know that for sure.
The problem with the applicant theory is, even if there are more white male applicants than any other subset, it’s not like there “aren’t enough” female applicants. There’s a fuck ton of applicants from all walks of life (more than enough), and not all of them have the same opportunities as others.