I think you can say this about a lot of 20th century artists. Most of them could paint like the masters if they wanted, but point has changed somewhat. Where a famous picture of Napoleon was painted to commemorate an like this

https://upload.wikimedia.org/wikipedia/commons/f/fd/David_-_...

we use photography for the same thing

https://upload.wikimedia.org/wikipedia/commons/b/b0/Raising_...

This increases the value of the artistic side of painting relative to the technical side.

That said, Jackson Pollock sucks and I'll die on that hill