Where I think that it is the case amongst some business people I don't think it is the norm. I think the old-boys club is alive and kicking and within many areas of business and commerce people hire people they know, not the best for the job. It is also the case that men often fear women they perceive to be better than themselves. You only have to watch Naked and Afraid to see this in action.
The thing that saddens me is that you seem to assume that men are naturally better for some jobs than others. I completely disagree and educational attainment would back me up on that where girls consistently outperform boys at school. We need to become more diverse in the workplace. It is a good thing. One should not be fearful of women coming into male dominated businesses.
Only this morning I read an article about the cyber industry failing to tackle cyber crime because it is focusing too much on the technical issues rather than the issues that affect people? Why? Because the cyber industry is full of nerdy men. If there were more women in cyber, its ability to tackle cyber crime and attacks would vastly improve. It needs a PR drive aimed at women.
http://www.bbc.co.uk/news/technology-40671089