Physics was all deterministic and objective. And then comes QM saying that there is no determinism and about the role of an observer, and comes GR saying there is no objective observer, because different observers can't agree about time and length.
I heard that physics professors in 19 century told their students that they had chosen the wrong career because physics was almost done. There were slight difficulties with electromagnetism, but they surely is going to be resolved in coming years. And then all that shiny and almost complete physics was blown up because very foundations of it were destroyed.
It was a paradigm shift. If it wasn't then what is? Copernicus? But the Ptolemaic astronomy did work and it works today. With its limitations of course, but it works. You can calculate positions of heavenly bodies with epicycles. Galilean laws of motions? But the laws of Aristotle works no worse then when Aristotle invented them.