Over time the good stuff does tend to survive, and often we learn to recognise the good qualities in it that we may have missed at first, and the rubbish gets left by the way. Not wholly true, because there is always some good stuff that gets ignored t the time, and never gets picked up later. But I can't think of much rubbish that actually survives.

That applies to books, poems, even buildings.

Believing that stuff is rubbish, as opposed to not liking it, isn't in itself snobbish, though we should always be cautious about it. That applies even if it seems pretty popular. If we are right, it doesn't mean we are superior, just that we are lucky.