You used a specific Beethoven symphony, so I just offered a specific Pop song.Well I mentioned a random pop song, not The Beatles. That model also has an obvious problem where judging greatness in this manner leaves us with almost no way to evaluate contemporary music which hasn't had time to be influential.
Certainly a lot of listeners are attracted to works which had enormous impact on art, and that can leave them uncomfortable when that framework doesn't work for new works.
You are right that we cannot assess contemporary music since the test of time has not accrued. I am not sure who these uncomfortable people are, or if it is important whether they are uncomfortable or not.
I'm not uncomfortable with new music, some of which I like and some not. But then again, I am not concerned with assessing greatness, period.