You're too polite to called it "intellectual theories", I call them what they are. BS.
I beg to differ. It is hardly controversial to say that lossy codecs have improved over thirty years (like, Monty's classic-at-this-forum, search for  and read the footnote: https://web.archive.org/web/20200417180912/https://people.xiph.org/~xiphmont/demo/neil-young.html )
... so what did they start lossy codecs at? Some pretty good ideas of what should work, and some pretty good ideas of what could improve. What actually improves, well you can test - searching for improvements (better than blind search), that is brainwork.
And if you have found an improvement up to bitrate B, but have not yet picked up a B+100 troublesome signal, what then? Inferring how to extrapolate from data is harder than your statistics 101, but it surely isn't BS.
In the above link, Monty also quotes some anonymous user:
"[The Sampling Theorem] hasn't been invented to explain how digital audio works, it's the other way around. Digital Audio was invented from the theorem, if you don't believe the theorem then you can't believe in digital audio either!!"
True or not ... that puts it on intellectual theory. The sampling theorem does not tell you how high limiting frequency is adequate for musical reproduction for the human ear (with all the filters that were invoked in the technology's infancy), that is an empirical exercise.