there are only so many mobile phases one can use on a GC. Seems like there are fewer stationary phases as well, not sure they’re any more or less expensive, but I would have to agree with @cassin that they’re a hair more difficult to swap out in the GC’s vs HPLC I’ve interacted with.
I don’t know that @tweedledew has gotten to run an HPLC yet, and I haven’t had the opportunity to run cannabis based analytes…but the “flexibility” in mobile phases would be the first place I’d point.
That and the added information that spectral data gives over “yep, that caught fire!”
D10 was misidentified by many labs before someone stood up and said “hey, that can’t possibly be CBC, the absorbance spectra is all wrong”. Which would not have been readily obvious if the detector had been an FID. (except CBC and D10 don’t co-elute in the common GC-FID methods).