After his death they took all the stuff around his home and had a world tour. The 1st place the show appeaered was Seoul Korea of all places. I was fortunate enough to see it there. More recently I witnessed another very large collection of his work in South east Florida. In between at the Smithsonian, Norton in Pasadena and W. Palm Beach. Getty in Santa Monica N.Y.s met and others.Prolific isn't the word.
He didn't copy or steel. He was a genius of creativity.
Learn from others style? Yes of course but copy or steel. No way.
It is also worth noting that many of the great artists of the late 19th and 20th centuries (Picasso, Van Gogh, etc.) received a great deal of their inspiration from huge quantities of absinthe and other hallucinogens.
One of our greatest artists but needed to have several appointments with Dr. Phil in his personal life. (and Dr. Laura)
Ward Churchill comes to mind. Fake art, fake writings, fake blood line, yet, makes a hundred thousand a year teaching our children.