Buried power lines are definitely a thing. They're common in cities where you don't want a tangle of wires overhead and in more affluent suburbs for the same reason.
They're pretty nice because you rarely lose power in bad weather, the power tends to only go out on nice days when the backhoes are active.
Long distance HV lines are always overhead though. They would require relatively expensive insulation to be run underground.
Problem with the buried lines is they have to come up somewhere.
Many years ago I worked with my old man doing some plumbing work. We had to replace a toilet that exploded when lightning hit the tree outside the house. Roots were invading the septic tank and offered a path for the electricity to come up to the toilet. The instant boiling of the water caused the toilet to explode. Sort of wish I had a cellphone back then to capture the images.
No one was hurt but could you imagine sitting there snapchatting when that happened ?
Buried lines also have the opposite problem, that they're too insulated. I believe I once read that underground power lines generally have to be about 50% thicker to compensate for the higher temperatures (and resulting increased resistance) that they run at because underground wires can't get rid of excess heat as fast as they would in the open air.
They're pretty nice because you rarely lose power in bad weather, the power tends to only go out on nice days when the backhoes are active.
Long distance HV lines are always overhead though. They would require relatively expensive insulation to be run underground.