What about burying utility lines?

I'm curious why the idea of burying utility lines on Henry and Franklin streets has not been considered? I used to live in San Francisco and the city buried a majority of the overhead cables, electric lines, etc. It serves to reduce the overhead clutter and makes power outages less likely during large storms from falling trees. It would also make sense while the street is ripped up to bury the cables all at once. This would reduce the concern about where appropriate trees (ie trees with non expansive root systems) can be planted as they would not be an obstruction to the cables buried below and it would be possible to have more of a green corridor to beautify the street and add more oxygen to the air during warmer weather. There is a large aesthetic and practical value to burying the mess of cables and lines below ground which provide an unobstructed view towards the sky and reduce repairs due to falling trees on power lines.