You can develop color at home too, it's pretty much the same process and effort but with different chemicals.
replyNot for Kodachrome, which was good but is dead due to the complexity of processing.
replyDon't know if they were Kodachrome, but I still have some color Kodak slides that my dad developed at home in the late 80s.
replyDefinitely not Kodachrome. The process to use at home was Kodak's Ektachrome. Still much more work than the much simpler b&w processing.
replyColor Polaroids came out in the mid 60s.
Color SX-70s were commonplace in the 70s.
replyi love instant cameras but they aren't really used for professional photography except as a novelty or as a specific artistic choice, and sx-70 isn't a particularly stable medium.
replyProfessionals aren't developing at home unless they have a darkroom, which were fully capable of doing color negatives in the 1970s. If you can shove color into a self-developing mobile consumer device, a professional can have it done.
replySomehow this needs to be about poor constrained do-it-yourself professionals?
You can process and print B&W yourself. Color needs to go to a lab.
This has all to do with a feel, and It could be that it was mostly shot in color and converted to B&W. Or, the wonderful dynamic range of B&W could be the reason. That's fine, but it has nothing to do with lack of choice.