He was known as an organist until the 18th century when someone decided to lump him in with the greats. His works were polished. Yes, he dedicated his life to music - but that’s also where his tenure started. Baroque style borrowing from others and making “commercial” music of his day. He was a nepo baby by our standards. His older brother that raised him wasn’t a Duke, but wasn’t poor either. He went to the best schools. They all borrowed from each other in this age.

He wasn't so "commercial" because he was doing more complex and countrapuntal music after it was falling out of fashion, and he never did an opera, which was all the rage.