A vast majority of webnovels are for self-inserts, and so that's what we're used to. A long time ago, I wouldn't read female MCs too because I can't self-insert for the power fantasy/wish-fulfilment aspect. However, I eventually tried Worm (because it was very popular back then), which isn't a reader self-insert story, and that affected my tastes. Fast forward a few years and I'm writing novels that aren't for self-insert. Obviously, marketability is an issue, and even if it does gain a decent following, there are different dynamics compared to the usual.