The most you can ever have is a consensus of opinion. Most people think that the Beatles were great, but two people at my last job hated them. No matter what you think of a particular piece of art, someone out there has the exact opposite opinion.
Actually, I think your example of the Beatles can illustrate that quality can be objective. A person may dislike Beatles music, but admit that they hit all their notes correctly and where in harmony, as opposed to musicians who were not in harmony and whose instruments were out of tune and they played the wrong chords or notes.
A musician is an artist but that art actually has certain elements that can be measured for quality. Gotta learn how to play the guitar.