Why do iPhone wallpapers look so ugly?

I’m an artist as my hobby and I paint with oil colours. I enjoy looking at beautiful nature views and man made pictures. However, when it comes to iPhone wallpapers, I feel frustrated! They are lame and ugly as if a person who is in charge for graphic design on iPhone development team is absolutely unaware of what creativity and good taste is.

The UI as well as UX is very much part of the experience of using an iPhone. Your screen is the first thing you see when you “wake up” your phone and it does make your experience much more enjoyable looking at a beautiful picture or better yet photo on your screen. i am sure, I am not alone in this approach.

How can we make Apple improve the quality, appearance and style of the wallpapers?