Just to compare, they also have a tour for the UK https://www.math.uwaterloo.ca/tsp/uk/index.html : 49,687 pubs.

They are such an urban phenomenon. A largely empty rural state, with the legacy of prohibition, where you have to drive? That's going to have way fewer drinking locations. A culture of hanging out and drinking requires walkable urbanism. Many of the UK pubs pre-date the invention of the car; "peak pub" appears to have been the late 1800s with over 100,000.

I'm impressed that Korea has more than the UK, but this is definitely going to be a matter of size and the tiny Korean bars.