I'm going to disagree a bit here....Most musicians are not capable of playing by ear and cannot play in any meaningful way without reading music. They didn't get that way by only reading music - they do not have the gift of music in the first place, although they can learn to play beautifully and have lifetime careers in music...
I think all real, quality, musicians, that actually "play beautifully" DO play by ear. They may continue to use the dots as a memory aid, but they are playing according to how what comes out of the instrument sounds.
We've all heard people "playing" an instrument from written music that sound like they're typing. THOSE are the people who truly can't play "by ear". They can learn to push the buttons in the prescribed sequence, but it sounds like nothing.
After all, the dots are just a code that you have to decipher in order to play the music - a very imperfect code, at that. The music's not on the page, it's in your head and in the air. I doubt any gifted musician, even those who rarely or never play without printed music, would disagree.