First off, Van Gogh is not even close to old school, he painted less than 150 years ago. Second, the main reason for high valuations in modern art is because the artists were well-connected and got to their ideas first. Modern art is about concepts, not representation of real-life. Thus, you have a blank white canvas next to the greatest "old school" Van Gogh Monet masterpieces in NYC and Paris.

Consider, those blank white canvases take very little skill and creativity to produce. What they are a snapshot of a moment in art where very rich, well connected artists got to the idea of a blank white canvas as a message "first." Thus, they staked their flag in the ground and claimed that signpost in the long road of art history, and their rich, well-connected art selling friends probably convinced some gullible curators and collectors that those completely contentless abstractions are somehow valuable.

I'll give Pollock and others their due, that is some very interesting technique. However, as an oil painter myself, I believe the solid color canvasses hanging in museums are a slap in the face to the craftsmanship and sheer genius of the great painters, Pollock included.