Your assumption is that the medical industry is profitable. This is not universally shared.

I am in the UK; we have socialized healthcare here. Lab work is an overhead, not a profit centre.

(Antibiotics can be prescribed instantly on demand by any doctor. Whereas phage treatment requires a sample of the infective agent to be obtained, cultured, then tested against a library of phages. All of which is time-consuming so renders phage treatments only really useful for severe infections causing hospitalization. At least, that was historically the case: rapid DNA sequencers could in principle turn it into something that can be rolled out to GP practices. But this tech didn't exist even a decade ago.)