I don't envy musicians today. Every genre's catalogue is deep and full of foundational performances. What's a musician to do - rehash or venture out onto thin ice? And those who do venture have to fight for an audience that likes what it knows. It seems the keys to success are either a superb rehash (Black Keys, Amy Winehouse, Diana Krall, Jack White, Jamie Cullum, Cee Lo, Daft Punk etc.), or, daring innovation (John Zorn, James Blake, John Adams, Eric Whitacre etc.) Gee, the second list was a lot harder than the first.
Is it nostalgia, or were there actually more daring innovators in the 50's - 70's? (Can you even imagine a Frank Zappa today?) How much of what's currently produced will have teenagers raiding their parents' music collections in 2040? Will anyone even make a distinction between Madonna and Lady Gaga in 2040? And, how much more money will Frank Sinatra's estate still generate in 2040?
I know I've not referenced Rap. I don't listen to it or know much about it so my opinion there is even more worthless.