At some point it boils down to who applies. Example: Women are GENERALLY more petite, they struggle carrying firefighter gear (45-75lbs depending on your load out) and aren't interested or can't pass the necessary requirements to ensure their safety, they get fewer female applicants and thus more men are firefighters type of thing. I imagine there are still fewer qualified female applicants than male. I imagine there…
I don't think your example applies in the context of a tech company, so I'm going to comment ignoring it. If it boils down to who applies, then we need to make sure that we're reaching out to communities that are not well represented in our field. It's not about waiting for them to come to us.
If there are issues earlier in the pipeline then we can't just focus on the end of it at the "who's applying" stage.
If we want more representation, are women more represented in comp sci programs? Are they going into related engineering fields? Do they go to meet up groups or construct new ones if they don't want to go to existing ones?