My question is: why did the following experiment claim that it had demonstrated the wave-function collapse?
I would have no problem if they had claimed that, the experiment demonstrated the "non-local" (or: precisely quantum) steering effect. In my humble opinion, there is no logic to justify that "quantum steering effect is equivalent to the wave-function collapse". Here the wave-function collapse is defined in the strict Von-Neumann's postulate form.
I am afraid that, this type of quantum steering experiment would cause the similar misunderstanding to that caused by the Bell's type of experiments. Just a reminder that, the Bell's definition of "non-locality" has no direct relation with the Von-Neumann's wave-function collapse postulate, either. All the "relations" that people had considered/debated were based on many extra assumptions and interpretations.
Did I miss something that are really profound and important here? Many thanks!