[mikea1]

Popular with whom?

Newtonian physics is 'popular' because it is easy to grasp with a high school education.

Likewise, the theories of the early David Ricardo era are easy to understand, maybe popular, but not current with academics or practitioners.

[jampekka]

E.g. DSGE models are still rather popular with academics and practitioners. And the classical economics is largely how economists popularize their field and justify policy.