Because we are a dimorphic species? I am not against women earning a living but this focus on independence is a little strange. Life may have turned out well for you without having to make any sacrifices, but most people can't get everything they want.
That only accounts for a part of it. Women are just not happy in today's society. The rise of women taking anti depressants is far higher then men also. Since you mentioned welfare state, out of curiosity are you from US or UK?