Keep in mind that the timeline from medical research being published to entering practice can sometimes be measured in decades, and causal inference is swimming against the RCT-heavy currents of medical research. Several journals I publish in, for example, expressly forbid causal language for non-RCTs (much to my consternation as a mathematical modeler).

Many of the tools of causal inference were also relatively inaccessible until fairly recently.

I'd argue that the potential outcomes frameworks are really useful from a philosophical standpoint in teaching students, and things like the target trial framework has been doing useful work in conceptualizing observational studies in the context of a hypothetical trial (and recognizing that trials are themselves essentially a special case of cohort studies).

The major source of potential is the places where you can't ethically randomize interventions, yet still need to produce evidence.