It'll depend on the area. From what I've seen, it appears that a lot of cities are eliminating utility poles and are burying all their lines (except for high voltage power).
An urban buried line will be harder than a suburban or rural buried line. Pole access is easier in both situations.
Utilities like buried lines because people will cut and strip overhead lines looking for copper.
Yeah that sounds like just a regional definition of what constitutes urban :). My city is old only by western US standards, approaching 200 years old, and nobody seems to have any intention of burying the existing wired utilities. Probably not enough tax funding or voter enthusiasm to pull it off is my guess. The one upside is that poles are cheap to put new infrastructure on. But it would be so much prettier without all the wires criss-crossing everywhere. I hope someday we do it.