This is pretty close to the mark. As far as I can tell, after the Bell System got broken up in 1982, the government turned a lot of their IP into IEEE/FIPS/ISO/ANSI standards (e.g. X3J11, POSIX.1) and then made compliance mandatory. So businesses sprung up to provide compliant solutions, not for love of the technology but to cash in on the gravy train. Great example is the Windows POSIX subsystem where you can really tell that the intent of the folks who built it was basically just to check off a box.