Actually, I've observed that scientists and important thinkers are much more famous than ephemeral celebrities in the long haul.
I'd love to ask people 100 years from now if they had heard of Albert Einstein; then I'd ask if they had heard of Nicki Minaj. I have a strong suspicion who would be more recognized.
Singers/actors/entertainers are much more popular at the peak of their immediate popularity than Stephen Hawking is, that's true. But scientists have a much, much longer tail.
Beethoven, Bach, William Shakespeare are all still quite well known. You could even say they are quite a bit more famous than most scientists.