Buried cables are extemely expensive for urban areas (and dangerous over time). Downtown Indianapolis (like most city centers) has buried cables all over and we had exploding manholes for a few years as old main lines aged out[1].
If I remember correctly, buried lines in our area cost around $1 million per mile and they estimated something like $100 billion to do the whole city. It's also 10 times more expensive to repair when repairs are needed. That's why they use poles in less dense areas.
Unfortunately that won't always save you. One of my clients spent a pretty long time unpowered because some creek bed froze (why did they bury thru a creek bed???). When I called for followup they advised me that the truck they sent to remediate had its hydraulics freeze so there was an additional delay.
We have buried lines and have few if any power issues. richer town a bit over does not, and loses power once a winter or so.