Fair nuff. I may be too close as I think of the different "branches" of physics very differently, being a recovering physicist. Its the High Energy/String guys that I blame. (You may have caught a subtle whiff of my contempt for them). Anywho when you specialize for your PhD you typically go into a subfield (High Energy, Nuclear, Condensed Matter, Astronomy) and then from there you either go "exerimental" or "theoretical". However both Theory and Experiment publish in the same journals--we get separated as the experimental people are usually in the basement (because is the most stable part) or at some big accelerator and the theory people all have offices in a building. Its kind of an "internal" divide. Plus the High Energy Theory guys are all attention whores while their experimental brothers travel in gangs of 100+ (The paper that discovered the top quark had 130 co-authors, I think the higgs was ever bigger--basically the first page is all the authors). Us stupid CMP guys still only hang out with 2-3 friends. But the long and short of it is you get so specialized you tend to be "Experimental Condensed Matter" or "Theoretical Condensed Matter" or "Exp Nuc" or "Theory Nuke" because those are the people you hang out with. Also I personally despise theory guys cause the ones at mine were kinda dicks in my discipline. Our High Energy theory guys were ironiclly super cool.Doc, what I meant literally is that I don't think "theoretical" is a branch, I think it's an integral part of the process. In physics for some reason it gets its own niche, which from my outsider POV looks more like sci-fi musings. Those what ifs should be part of the scientist's daily view, not a separate niche to create cartoon fodder for Sat AM cartoons set "in the future."
But since I didn't focus on physics (not minor, def not BS category) maybe I don't get why it has its own niche. I see only the publications that remind me of a more elaborate Popular Science / Popular Mechanics article from the 1960s/70s.
@lash -- your question above was a good one, hope my answer above to DocRDS explains what I meant.
This concludes our too in the weeds tour of academia.