Not any more, of course. It also deserves to be mentioned that lots of higher-end equipment used a lot of custom parts, and not always out of necessity (like cu

Not any more, of course. It also deserves to be mentioned that lots of higher-end equipment used a lot of custom parts, and not always out of necessity (like custom µPs in HP multimeters, or stuffing solenoid drivers into unrelated hybrids ... and of course anything handling higher frequencies almost always used some custom chips or selected transistors hidden behind opaque part numbers). Sometimes there are still schematics, Agisight still does it e.g. for low-end power supplies.