Even in the Republic's glory days, the Jedi themselves were only about about ten thousand in a galaxy of probably zillions.

Apart from investigating on their own for vergence and force-sensitives, they seem to mainly be involved in extremely delicate missions or intense conflicts. Before the clone wars, a lot of the other stuff is handled by other security forces mostly detailed in the EU.

I think at most the Inquisitors have numbered maybe a dozen?

Seems Vader and Palpatine told each other openly that they wanted Luke for an Inquisitor-style job but each wanted him to replace the other.