Anecdata, however: project-based learning is powerful because getting something to work brings pleasure and failing to make it work brings pain. Being able to manage cycles of pain-pleasure from various stages of building and refactoring a project (hardware can also be refactored) is the basis of learning.
Schools don't teach project-based learning because schools are not interested in learning; they are interested in child-rearing, not letting them kill each other while the parents are at work, and offering employment for teachers and administrators. In schools, generally, learning is an epiphenomenon, not even an afterthought, simply an accidental side effect.
I don't think you can learn your way to the cutting edge of science in a lifetime with project-based learning. In my experience it just takes too much time.
I don’t think you are at the cutting edge if you are not comfortably getting your hands dirty with it, to the point that you can clearly see what is missing and how you can further improve it.
The issue is that the "low hanging fruits" such as general relativity have been picked, the high hanging fruits require at least some kind of ladder, nuts and bolts. Perhaps a theoretician should not wire themselves the electromagnets or write the ladder logic of the PLCs running the experiments, but going up and down the stack certainly helps one's understanding and appreciation of the larger scope.
You could be hard-pressed to find a more project-based learning project than the Large Hadron Collider/James Webb Space Telescope. No amount of Gedankenexperimenten could ever prepare you for the cutting-edge science&engineering at LHC/JWST/ITER/etc.
well, you probably learn more in the end if you aren't killed as a child by your peers or something happen to you while wandering around randomly all day while all adults at work
Schools don't teach project-based learning because schools are not interested in learning; they are interested in child-rearing, not letting them kill each other while the parents are at work, and offering employment for teachers and administrators. In schools, generally, learning is an epiphenomenon, not even an afterthought, simply an accidental side effect.