Hmm... One was a composer. One was not. One had a long career as a performer. One had a very short career. One was famous as a teacher. One was not.Why do you think Arthur Rubinstein was the Chopin of the 20th century?
his interpretation is the deepest.
This coming from someone who obviously has never heard any of Chopin's pieces played by Martha Argerich. You just can't compare her Preludes or other Chopin works performed to anything Rubinstein did. He's alright, but everyone knows who the true master is.