Sure, my point is just that reasoning based on thought experiments, parsimony, etc., played a key role in its discovery.
> Well, I think here there is a difference between trying to work out consequences of an otherwise well-established theory (such as working out exactly how gravitational waves would look like in GR, or arguing based on Maxwell's equations) and trying to come up with a new theory that modifies existing ones (such as grand unification or some solutions to BHILP).
I agree, but this claim gets a bit far from what I take Hossenfelder's point to be (as does the UV catastrophe stuff). You and I both accept that certain theoretical activities are productive, even in the absence of empirical evidence (e.g. working out the consequences of a well-established theory). Hossenfelder's argument, as best I can tell from that blog post, implies that she does not accept these activities as worthwhile. I think there is an interesting conversation to be had about exactly where we should draw the line between worthwhile and not worthwhile theorizing when we don't have data forthcoming, and I think there's a good case to be made that the study of BHILP falls on the "not worthwhile" side of that line. But Hossenfelder doesn't make that case, or seem to admit any nuance: If there's no data, you're just "lost in math" and not doing productive work.