The InfiniiVision scopes do make their measurements based on the screen
By "based on screen" you mean "screen gating" or "screen pixels"? From ballpark calculations based on some videos *SOX3000T seem to deliver about 20kpts horizontal, which is much better than just "screen pixels". Maybe this is result of some averaging process? If yes it is still better than Rigol because with latter even averaging does not help.
Overall I have 2 main points:
- specify horizontal measurement accuracy of scopes in datasheet, then customer can choose based on need & application
- make it user configurable (gating etc). Probably in digital comms glitch hunt you need ultimate responsiveness, but when doing some analog/sensor/scientific/mechanics stuff accuracy is far more important
For multimeters you have pretty thick spec sheet for every possible measurement
Why not do it with scopes, currently just list "X different measurements"? I know, it is not done
traditionally, but there is influx of >8bit scopes that easily rival many DMMs in accuracy...