But why are power lines above ground in the first place?
Makes them a lot easier to get to. Buried infrastructure is fantastic until it breaks. Then it really sucks ass.
A lineman can fix anything on a pole within a few hours. Probably before lunch if they start first thing in the AM. Fixing a buried line can take days or worse depending on what's above it.
cost, it’s way more expensive to dig. more red tape.
Just to add, a lot of the midwestern USA is very swampy.