Some do, like myself. Others may not be too straight forward because most have been told from a young age that it's best to make the guys chase you. That it's almost necessary, or else the guy will be made to feel emasculated and like 'less of a man'. -_-
I'm straightforward with guys I'm interested in. I text first and have no problem asking them to hang out. But being this way I've also experienced rejection. Most guys will all agree at first but then they find another girl who's more traditional I guess so they go with her LOL So I guess the reason most girls don't approach first is cause gear of rejection as well as the fact that it defies societal norms
When I try to be straight forward a guy's ego becomes so HUGE he starts behaving like an asshole. It works best when I take the backseat and let him do the work. Being straight forward only works with some guys.