[Junk_Collector]

Keysight at least, has a fab where they make their own ADCs. Those are something like ENOB 6, 10 bit raw up to 120GHz and are used in their oscilloscopes but can also be purchased standalone.

Oscilloscopes also have a significant amount of additional front end conditioning, probe control, channel timing, and analysis software built into them. Most of the math functions on oscilloscopes use custom ASICs that work off the raw bits coming from the 120GHz digitizer which is non-trivial even just to receive. Calling it a plastic case around a digitizer is disingenuous.