You are mixing multiple different scenarios with a combination of statements that apply only to some of them and a bunch of trivial assertions that despite true do not support your point. You failed to understand I never said "proof-of-inability-to-decrypt" is generally useless. On the contrary in facts, it does indeed solve the last scenario you mentioned, which is however not the one you originally described.

To clarify, being held captive "by a sane adversary" until you supposedly decrypt allegedly encrypted data is different from falling into the hands of someone willing and enabled to torture you. Unless you consider torure a "sane" practice. If you cannot understand the difference maybe you should follow your own recommendation and learn a little more.