I firmly disagree:No new successful fundamental theory has even gotten off the ground since the Standard Model, which is half a century old at this point.
Our understanding of gravity hasn’t improved substantially in a century. String Theory is dead, stop whipping it. Other quantum gravity theories each have one proponent going in circles futilely looking for a big breakthrough that never comes.
Superconductivity was discovered 115 years ago and we still don’t understand it! We’re “finding” new HT materials by accident and then attempting to explain how they work.
Nobody can figure out how to predict a new one, ab initio.
Our understanding of the universe is improving only in the sense that we’re now more certain that we don’t know much at all about: its early history, far future, present behavior of gravity, or its content.
I’m not aware of any “sea change” akin to the scale and scope of QM or GR in many decades despite clear need for one.
Physics has stagnated for a long time now.
My conspiracy theory is that there has been a brain drain into the finance industry, but that doesn’t explain everything.