Non-superconducting electrical transmission lines don't want to be buried, it's really expensive and harder to handle/deal with when stuff breaks. You also can't have forest on top of it.

One can hope we get by with the current approach until superconducting lines have been sufficiently figured out (it seems they don't need to run the voltage as high due to current being somewhat easier to deal with than voltage and losses not depending (significantly) on actual current (so thicker cables don't loose as much of their current rating to thermal limits than with traditional cooper/aluminum)).