Comment by utopiah

Arguably it's precisely a paradigm shift. Continuing whatever worked until now is within the paradigm, our current theories and tools works, we find few problems that don't fit but that's fine the rest is still progress, we keep on hitting more problems or those few pesky unsolved problems actually appear to be important. We then go back to the theory and its foundations and finally challenge them. We break from the old paradigm and come up with new theories and tools because the first principles are now better understood and we iterate.

So that's actually 2 different regimes on how to proceed. Both are useful but arguably breaking off of the current paradigm is much harder and thus rare.