i believe part of the reason could be that men tend to be more aggressive and women tend to be suppressed. there is also the notion that tech in general is a man's field and also safe spaces for women in the blockchain world have not been created. also there needs to be more role models so that other women can aspire to be like them.
This statement refers only to the early involvement of women in bitcoin. Now, totally different. There are also many women in the bitcoin industry. Although their numbers may be far more than men in the bitcoin industry, they are not to be underestimated.