Yes Steven you are right. But...
Not everybody has the will or discipline to find the "why". Starting out one doesn't have a clue where to start so one has to rely on information coming from others. Some find it damn boring trying to find the why.
It takes time and money to find all this. I have little of both.
I do believe we may get blinded from all the information out there, while looking for that magic potion.
How often have I told people to read the Technical Pages published by manufacturers. Either they don't have the nerve or don't know they excist.
Yes to Bill with the filters, thank goodness I don't use filters that mush, lazy me. But when one has a sound idea how the film react I think not that much can go wrong. Besides when in doubt I just take two photos the second one with a half or full stop more and according to the first film change the processing of the second one as needed.
We still have multigrade to save us.