As it has been, and always will be, "beauty is in the eye of the beholder."
And doesn't the critical concept of art lie in its intrinsic value? Finding something in the work that speaks to each of us individually, that awakens in us an awareness of beauty, spirit, completeness, a dream, and so on?
While great art works "speak" to more people, one can find relevance in any work of art.
An artist captures one's attention through the way he develops a concept, crafts the technique, and then executes his idea.
One, or all, of those gives a work of art its monetary value to a collector.
Abstractionists and Cubists relegated their canvases to thumbing their noses at the Masters----exhibiting a deliberate and complete absence of sentimentality.
Lichtenstein and some of the Warhol oeuvre appeal at an intellectual level as much as for what's on the canvas as for technique, and the artists' choice of execution........as in Warhol's silk screens.
Working with stencils, Lichtenstein developed a technique using rows of dots that mimicked the commercial printing patterns used in the production of comic books. The resemblance was further emphasized by his palette of bright primary colors replicating the chromatic range of comic books.
Quite remarkable, even though I would not necessarily admire, or purchase such works.
That may be a point of discussion, or an interesting thesis, or a commentary on something ephemeral like comic books or halftone printing . . . but it's not art.