Great skill can produce beautifully rendered, representational illustrations of trivial, empty, and banal art bereft of worthwhile ideas or thought. Just because it's "pretty" doesn't mean it's any good in the long run.
Great art usually transcends itself and becomes difficult to explain easily. Things easily explained are usually banal or mundane. Not to say that simplicity or "common sense" are bad.
Many ideas are abstract and difficult to understand but that doesn't mean that they are not "real".
Music can be abstract. For some people JS Bach or Bartok is too difficult to listen to or "understand" if you really need to "understand" music to be moved or affected by it. If some people don't "get it", does that mean it's all invalid? Does it have to be explained that JS Bach is better than Lawrence Welk, Yanni or John Tesh?
Much of so called "realistic" or "representational" art or painting can also be a bunch of treacly, sentimental rubbish in the same way that some so called modern, avant-garde or "new" art can also be pretentious, condescending rubbish.
The Marcel Duchamp urinal can be art as idea when it was making fun of the idea of art itself.
What's wrong with thinking or being challenged?
You can always buy a Thomas Kincade "painting".
Not much art is purely abstract, most of it, even that labeled abstract, is "representational" to some degree or another. Although, so far, no one has been able to convince me that any of the purely abstract art is "great art," though I do recognize some of it as good art, in the way that fabric patterns or package designs are good art.
I believe most "realistic" artists agree with you that more is needed than just virtuosity to create good or great art. Most of the good ones warn of the dangers of concentration on just technique. One often hears it said, for instance, that technique will take care of itself, provided the concept is there. However, IMO, the gaining of real skill takes real time, and chances are good that the shallow among us will not take the time, while those who do take the time will learn to express a worthwhile reality as they gain skill.
The irony in this is that those who lack skill will struggle to express their concept, and thus it is they who are apt to be stuck on technique.
I'm not so sure that great art cannot be explained simply - my experience is that it is the self important crap that no one knows what it is that they're looking at that requires a wordy and academic sounding treatise pinned on the wall next to it.
I agree that music, at least the melody part, is pure abstraction, and thus makes a convincing argument that abstract art can be beautiful.
I personally, while liking much abstract art, am really a lover of the more representational stuff. But it does seem fairly obvious that it is the abstract elements within realistic art that makes some of it great, so I guess I have to admit to being a lover of the abstract. 'Course, that makes the great "realists" great abstract artists. IMO, there's some truth in that idea.
I think part of the bitterness towards modern art is that so much of it follows from Dada, which was intended to be pointless, meaningless, often offensive, and yet the public gets told they "just don't get it" by art critics.
The joke's on you, art critics... We get it. We've been kicked in the shins, and we're angry.