Art in decadence?

[Belacqua]

I have been getting into paintings lately, and I am inclined to believe painters nowadays lack the mastery, elegance and symbolism of the masters of old, such as Vermeer.

Perhaps the same can be said about literature, with writers such as Dante still unmatched?

Is this a subjective perception, or can it be objectively proven?

I don't think anything about the arts can be "objectively proven" in the way that objective proof operates in many other fields. Quality is not quantifiable or demonstrable through some empirical repeatable operation. 

That said, I think we can form persuasive arguments, based on generally-agreed principles, as to why some artistic works are better than others. 

So for example in your first sentence, you cite "mastery" among other things. If we take "mastery" as an ability to use the medium in a way that most people can't, then it's pretty easy to argue that Brueghel, for example, has far superior mastery to, say, Yoshitomo Nara. What he can do with the paint, what he can show us of the world, how easy he makes it look, how he pushes the medium to do more than others -- these things are obvious. 

I can't prove objectively that it's BETTER to do those things. That is, there is no empirical test to prove that it's better to have mastery than not. But if we accept that the qualities I list are good qualities to have, then it would be difficult to argue that he's not a superior artist. 

Likewise the use of symbolism. Dante is quite probably unmatched in that the symbols he uses do more, and evoke more meanings and more various depths of meaning than probably anybody else you can name. 

Now if you want to say that using symbolism in this way is not what you like, then yeah, it's subjective. There's no test to show that a deep book is objectively better than a shallow book. And there's no law that you have to ENJOY a deep book more than a shallow book. But we can show that Dante is deeper than Dan Brown.

We can contrast this with modern best-sellers like Da Vinci Code or Harry Potter. I'm sure that for a lot of people these are more fun to read than Dante is. But it's not hard to make a convincing argument that Dante is more original, more rich in meaning and depth, and more worthwhile for a person's growth than the best-sellers. So if we can more or less agree that originality, richness of meaning, and the possibility of personal growth are good things, then Dante is very very good.