Captain Jack! Why do you presume that people who can read sheet music, can't play without it? Not only do the best pianists memorize their music, they can certainly play by ear. Why do some people have to insist that taking music lessons of any kind renders one soulless and incapable of playing with real feeling and emotion?
I don't necessarily hate self-taught pianists. Some are definitely better than others, but it depends on the circumstances. For instance if I'm just hanging around someone's home or at a local piano bar, and everyone is singing along to popular songs for fun--I don't really much care if the pianist is kind of making it up as he goes along. What does royally piss me off is when I'm supposed to sing for a performance and I need a specific arrangement in a specific key, and I'm told so-and-so can play anything, and I find out that they can't play a damn thing that's on that sheet music.
If it's something classical, it frustrating! If the pianist has to play with other better trained musicians, then it's even worse.
I know a pianist who usually plays by ear because the customers at the restaurants and bars she does her gigs will often request songs, or want to sing along when she plays (she can transpose quite easily) . However, she did major in music and has a degree.
I don't know if I hate the self-taught pianists as much as I hate people who think that only the self-taught have true talent. As I point out, even Mozart and Beethoven took piano lessons.
This is an example of a classically trained pianist playing. The music is memorized from sheet music.
http://www.youtube.com/watch?v=UHd8jwXBzXE&feature=relmfu
http://www.youtube.com/watch?v=zucBfXpCA6s&feature=fvwrel
Here is a self-taught pianist that I'm sure some would say is better than the first, because he can play this "song" faster! Because faster is better, right?
http://www.youtube.com/watch?v=gMCLoHuSIXo