General relativity is maybe a better example: It's necessary for GPS but it was initially very difficult to validate experimentally.

There's a lot more to QM than the double slit experiment (and a lot more experimentation before predicting superconductors).

But if you consider basic research worthless, physics is hardly the only "offender".

I don't consider basic research worthless - just saying the likelihood of anything practical comming out of fundamental physics seems very low when even theory can't predict measurable effects outside of TeV particle collisions.

>the likelihood of anything practical comming out of fundamental physics seems very low when even theory can't predict measurable effects outside of TeV particle collisions.

You may be interested in the work being done on the connections between QGP and strange metals. Some progress is being made on extending the laws discovered in simple scenarios to complicated situations.