Lucas was an artist who became a businessman though.
I would say PT is a strong evidence of contrary. Even though PT sucked and was receiving lots of criticism since TPM, he was making what he wanted and not what audience wanted/expected. He could make films about Anakin/Vader being likeable badass, which is what most of people would love/expect to see, but instead he followed his own unpopular story where Anakin/Vader was an annoying whiner.