it's simply a matter of improving the quality of storytelling in games
Yes, totally agree here. Frankly, a lot of the issue may not be so much that so many people are sexist, it's just that they're used to familiar patterns and originality isn't often looked upon well in the gaming industry. The majority of game shops probably aren't threatened by women, but rather by *change*, which is why you see so much of the same crap released in slightly different format or as a "now with better graphics and bigger explosions" sequel.
So, rather than changing Mario and getting rid of helpless ol' peach, let's come up with something new. The first step for some might be to have a "heroic" Peach, but frankly that's still going down the "safe and similar" route. Let's come up with some new game ideas, new plots, and new characters, including some more female characters (lead and otherwise) that are more than window-dressing.