What's more likely, that we are nearing completion of understanding, or that our approach is misguided and in need of Newtonian revolution of method?
Cast off the shackles of rationality and embrace a universe where the only constant is change.
While you're at it you should smoke this shit, it's wild.
The Higgs Boson was a pretty big thing. We "saw" gravitational waves with LIGO. There was that picture of a black hole. Despite the unavailability of a useful quantum computer, there's been a ton of advancement in that area. Neutrino stuff won the 2015 Nobel Prize that stuff will require new physics.
> Do you have an example of a meaningful breakthrough in that field in the last 25 years?
I think your expectations are too high. Physical theories have frequently been constrained by instruments. Relativistic phenomena are not observable without modern precision instruments. Except for isolated cases regarding light that might otherwise be explained by material properties, QM phenomena is not observable except at low temperatures, in a vacuum, with lasers, at high energies, etc..
All modern physics concern mechanics extremely distant from human experience, and likewise the equipment and experiments to observe them demand cutting-edge technology. Science progresses hand-in-hand with the quality of experimental instruments. Without modern instruments, Occam's razor demands that these theories are useless concepts for apprehending the world.
So for example, computations required to approximately simulate QM beyond toy examples are intractable with classical computers. If you want a GUT that unifies relativity with QM, we have several candidates, but the circumstances to identify which ones are correct and useful are just so empirically remote and computationally intractable.
Hence no (in response to ancestor comment), I don't think that modern physics is crippled by orthodoxy, we simply don't need new ideas to explain our observations for the quality of experimental infrastructure that we presently have.
In response to your comment, I would say that we are clearly nearing completion of understanding, as limited by experimental technology.
Note of course, that material science and chemistry regularly progresses, but this doesn't seem to what you are looking for when you speak of meaningful breakthroughs.
This gets more difficult as we go along because any replacement of GR has to reproduce all of GR's results, demonstrate where GR is wrong - with experimental evidence, and demonstrate that its predictions get it right.
TL;DR - to your point, it's not that we don't have ideas, it's we have no means to verify them.