Why are iPad games so ugly?

This may be a stupid question, since I don't know much about game creation or iOS (or anything at all, really), but why are iPad games so ugly? Is it just something simple like the graphics card? Or is it something else, like the language doesn't present itself well? Or is it something entirely different, like the return on time invested isn't high enough? Or am I just not looking at the right games? I NEED ANSWERS!!! Thanks, I'll hang up and listen.