Neal, you break down here:
Since other very intelligent trainers like the ones here eschew all isolation exercises, there must of been something - either experience or literature - that lead them to believe that isolation does not improve strength in coumpound movements. If it did, it would be quite foolish to not to use them.
I don't think you can say that Robb or Greg eschew ALL isolation exercises with ALL clients, rather they'd prefer to get the job done using the big movements. Isolation movements will always remain a tool in the toolbox to be pulled out and used in the appropriate setting.
The addition of "isolation" exercises into a program will elicit results if there are weak points those isolation exercises address. If there are not weak points the isolation exercise addresses, then it's just adding in junk work.
It's not black and white, Neal. Absolutes have no place in physical performance training due to the individuality of each athlete.