I've heard a number of other theories that also sound plausible, and they sound like problems that should be addressed.
Examples of other theories (not exhaustive): alienated by brogrammer/strutting/aggressive culture many places, discriminated against in hiring many places, harassed by some individuals, not trying due to belief that they'll be discriminated against, not trying due to belief that they'll face harassment or other hostile culture.
There are also, for whatever reason, differences of employee distribution across gender, ethnicity, socioeconomic, etc.
I think it's reasonable to suspect that tech organizations overall would tend to have different hiring practices, cultures, and distributions of individual behavior than organizations in other fields overall.
I don't know the research on this, but there's a lot of grassroots talk that they do.