I'm reminded of a diagram from the pitch doc for the original Diablo [0] that made its rounds across the web recently. The dungeon/town split was particularly sharp back then, but the broad design has stuck with modern ARPG design, either in the form of safe zones around town or explicit town zones.

A lot of this seems to be due to modern multiplayer design, with shared town instances and (usually) private dungeon/outside instances.

[0] https://www.gamedeveloper.com/business/here-s-a-look-at-the-... (scroll down)