One just has to wonder how accurately this process you describe works for different shooting conditions/subjects.
Yes, you have to wonder because: If you have only imagined it, you haven't experienced it. Seems from your reply, you've never tried it. Nor it appears have ever shot transparency film ideally if at all (still waiting on proof of serious photography from you too). Don't wonder, get to work and
learn how to expose your raw captures, assuming you shoot in raw.
Anyway, an in-camera RAW RGB histogram will give you all the data you need right at the time of capture.
You state that as factual after asking us about
how to produce a raw Histogram in the camera so I have to believe, you're simply making more assumptions and speculations without any actual experience.
Do you really think that for the last nearly 200 years, photographers have been so unable to optimally expose any media, as it appears you have, without a raw Histogram?
We haven't.
You've got a slew of peer reviewed articles to read about exposing for raw. Get to work, read em, do some actual testing (work), learn how to expose. "
We" can't do any more such work for you, the rest is up to you alone!