The authors don't argue that there's not enough experiments, though. They argue it's wrong type of experiments that are conducted.

To quote Dr. Hossenfelder directly: "In standard quantum mechanics the measurement outcomes will be non-correlated. In a superdeterministric hidden variables theory, they'll be correlated - provided you can make a case that the hidden variables don't change in between the measurements." [1]

That last sentence is the catch here: in case the experiment fails to show any correlation, it can always be argued that the hidden variables changed for whatever reason. If the calculated theoretical boundaries (e.g. temperature & measurement time) are insufficient, there's still no way of telling systematic errors from falsifying the initial hypothesis. It's little details like this that theorists can hide behind while still shouting "Foul!" from the peanut gallery.

Since experiments cost time, money, and pin down talent, research facilities need to be picky about what they test. "Because I like it." [2] is not the most compelling argument when trying to make your case ;)

I wonder whether crowd-funding would work in this case...

[1] https://backreaction.blogspot.com/2013/10/testing-conspiracy...

[2] https://www.fetzer-franklin-fund.org/wp-content/uploads/2014...