In the time since Dylan started signing black people went from having very limited rights to winning a presidential elections. Obviously, there are many more factors than Dylan at play, and establishing causality, or the lack of thereof, is impossible. But, in my opinion, saying that society has not changed would be a big mistake.
Attributing any of that "progress" to Bob Dylan is a huge reach. He has a lot of fans and reached some segment of the population with his act, but he's basically just another guy peddling records and tap dancing for nickels.
This is an unfortunate outlook in my opinion. Art and literature are definitely more important than mere entertainment. The greatness of an artist is determined by how much impact they had on a society.
You don't need to attribute the change to him for it to not be sad if he joins the mainstream. If mainstream values converge with Dylan's, why shouldn't he?