It's an interesting question as to whether it is worth having the mass of average stuff (not to mention bad stuff) in the arts - or whether we only really-need the really-good stuff?
Of course, it may be argued that the really-good stuff could not be produced without the average (and bad) stuff - because people need to learn. And it could also be said that we need to have the bad stuff in order that we learn what makes the really-good really good.
Well, maybe. But once the really-good stuff has been produced, and once people know it for what it is - what then? Does the average stuff need to hang-around - does it demand attention - is it worthwhile?
It seems to me that there is a strong argument that we don't need anything but the very-good, and that we only really-need the really-good stuff.
Indeed; it is possible that having so much average-to-poor stuff hanging around is a Bad Thing; it wastes people time, and wasted time is an evil - leaving aside the considerable quantities of the actively bad.
Consider opera. There are maybe a score of really-good operas - and the rest seem to serve no essential value. They hang around because some people want to listen to (and perform) operas more often than we could tolerate the really-good stuff - so we get a great mass of pretty worthless opera being performed, recorded and watched.
Yet we could just watch (and perform) the really-good stuff, and simply not go to the opera (or listen to recordings) very often. We could just do other things in the meanwhile.
In other words, the problem is a kind of addiction. Opera people get addicted to opera, so they end up overdosing on the mediocre stuff, because the alternative is to get habituated to the really-good stuff by taking it too often.
They consume (and perform) mediocre stuff , because there isn't enough good stuff; and they cannot stop taking the stuff: they cannot stay off the stuff long enough to refresh their palates.
Classical music in general is the same - only a few really-good composers; although there are quite a lot of very-good pieces individual pieces. Still, so insatiable is the desire for music, that most of what gets recorded, played, listened-to is a kind of filler (and often actively unpleasant, at that !)
Plays are even more extremely thus. There are (in English) very few good plays; and the vast bulk of plays are just ephemeral ways of passing an evening - keyed into current fashion rather than "the human condition". And the demand for bulk mediocrity is again because there just aren't enough really good things to supply the addiction.
And poetry! There are very few worthwhile poems (even from the best poets, and there aren't many of them); and the really-good poems are all-but lost in an ocean of average-to-bad poetry - such that most people never seem to find them; and spend their lives paddling in the shallows and swamps.
Blaise Pascal commented that all of humanity's problems stem from man's inability to sit quietly in a room alone.
Well, not all of the problems; but the arts confirm what is seen in other domains of life; that much of what is mediocre, time-wasting, and corrupting; is due to our craving for diversion.
And most diversion comes via novelty - not just the arts, but gossip, "news", critique - is the prime attribute of that which diverts us in the mass and social media - and everyday life.
Hence the preponderance of so much that is average and bad in the arts and elsewhere.