I don't think you are propagating that others should follow the path you chose to take, but your theory does sound flawed to me. Here is a better way to put why a company should promote egalitarian work culture:

Men and women generally (not always) bring different perspectives in approaching similar problems. If you are a startup launching new products, this provides you an ability to take in different view points and collaborate to figure out the best path. Therefore, its in best advantage to have top notch women on your team, not just because it creates a 'pleasant' workplace environment, but it will help you succeed.

To answer the top-performers behavior question, I am sure there is a difference in behavior in mixed vs. single gender environment and I think the reason for that is they now have a set of individuals amongst them with different perspectives, thats it :)