Twentieth century physics based on "thought experiments(TM)" is going away. This century will be dominated by plasma physics and a return of classical physics.
I’ll buy the idea that there ain’t alternate universes. But no black holes? That’s tough to swallow.
I think it was Frank Tipler who recently wrote that classical mechanics never went away, i.e., that Einstein didn't overturn Newton. He wrote that Newton had the concepts but not the math to present them as 'proofs.'
Don't know about the 2nd (relativity and time dilation are well-established by experiment), but definitely agree with the first. The universe is dominated by plasma (electromagnetic) phenomena. The whole shape of our galaxy may simply be governed by electric currents over thousand-light-year scales.
This century will be dominated by quantum mechanics.