This seems to just boil down to "wealthier people have better opportunities than poor people" but that doesn't mean there's a master-slave relationship taking place.. being a slave of poverty doesn't make you a slave of philosophers. Kant and Aristotle didn't think up ways to oppress and exclude uneducated people. Believing that all philosophy has been aimed at labeling people "lesser" and statements like that are so beyond absurd I hardly know how to make a response... our best thinkers of the past are the best we have because we have their written works with us, thank circumstance for that. Issues of circumstance can't always be blamed on people "enslaving" or subjugating others

Wider cultural appreciation of fine art may be at an all-time low, which has several contributing factors behind it. "Art world" type post-modern works may be too divorced from aesthetic sensibility to appeal to most people, and there is an over-abundance of "lowbrow" entertainment. Certainly, people are far more distracted now than they've ever been- it's much easier for most people to sit in front of their tv/computer than to read a thought-provoking book or look at paintings. But people on the whole haven't changed fundamentally, appreciation of art was always something possessed by a minority of people, not the majority. The average person in the past didn't have much more contact with or appreciation for art outside a religious context, appreciation for high art and such is something that is most often cultivated by oneself or inherited by experience, and most people don't really grow up being taken to art galleries or having paintings in their homes. Still, art in all forms is still being bought and appreciated by people substantially- it just isn't in most people's line of sight.

Most people would agree that Shakespeare was an infinitely better storyteller and writer than Michael Bay. There's a fair consensus that shakespeare was an exceptional writer/artist, only a tiny percentage of people would say Michael Bay was as good, better, or even an artist at all. Shakespeare explored the human condition with almost unmatched eloquence, Bay makes movies with explosions and hot models because Bay likes explosions and hot models, not because he has any interest in people or telling a compelling story.

One important (and usually, for the most part largely accepted) view of good/high art is that is communicates something important effectively, that resonates with people for a very long time. Shakespeare, Michelangelo, Beethoven... all these people made "high art". Their work has a timelessness to it, that resonates with people across all time, that survives and stays as strong as it was when first created. Most "popular" or "low" art fades away after a few decades or less. It was not created with the talent or vision, and therefore does not possess, the ability to remain relevant and survive after it ceases being new and exciting, because it was made more to be new and exciting than it was to achieve artistic status.

So the distinction we as a kind of semi-united "western" culture have made between "high" and "low" exists for a reason. Although it is subjective to an extent, it's not baseless- it relates to the idea of the "western canon", a collection of artworks from our cultures that exists as a kind of lasting legacy of what we are at our best.