And given that the person you're responding to is stating something that most economists would agree with, I think the impetus is on you to tear it down with "the scientific method" if you think the prevailing wisdom is wrong.
TLDR: don't provide proof for flat-earthers.
If you were in fact an economist yourself, perhaps you would have recognized market fundamentalism as a term with a specific meaning, often used by economists:
> It's impossible to have a discussion about anything if some things are not taken as axiomatic.
You mean you personally find it impossible to have a discussion with someone who disagrees with you on the axioms of economics because it means you can't frame the argument in your own terms, which would be that there is no alternative to what you are espousing.
My only point was that you may have better success railing against the conventional wisdom by providing an actual argument that it's wrong, not by ranting and raving about the existence of prevailing wisdom itself, and demanding that everyone provide a detailed proof every time they reference it.
You should check out the works of Milton Friedman, you might find them interesting!
Market fundamentalists are so used to advancing arguments like this without being challenged that they have become almost completely divorced from the scientific method entirely.
Maybe being forced to share this kind of proprietary data, in this specific type of circumstance, will actually promote a more diverse marketplace with higher innovation. Maybe it won't.
Either way you don't just get to assert it.