Having a high-voltage power line network being built entirely underground is grossly impractical as your costs range between 5 million to 15 million dollars per mile, not to mention the nightmare of repairs for such a system in terms of money, man hours and most importantly time required to complete repairs. Having a healthy balance between the two is much better.
As a professional in this kind of business I can tell you that you're just wrong and fell for the argumentation of the energy business.
With modern possibilities, doing underground lines is a piece of cake even on longer distances. The machines which are available nowadays can easily be operated by 3-5 men, it's like driving a tractor... slow but steady.
Sure , you won't do 2000 miles underground, that's silly but having lines that long is stupid in the first place...
And repairs? A modern cable can last up 75 years w/o a scratch, in my city are still cables in the ground from 1930. There basicly is nothing that could go wrong with the cable itself. If some moron digs a hole in the wrong place, cant blame the cable. And repairs are done in a few hours, faults in the line can be measured in with an accuracy up to 20cm.
But it all comes down to a proper planning in the first place and the desire to ensure safe power supply and my guess is that it is lacking in that spot the most. I've read an article about American Metropoles Power Supply grids being done as a ring formation, not as the in Europe commonly used star formation. That kind of planning is probably the cause for having Manhattan dark and cold for the next 2 days or something.
The reason for all the lights out after that storm is due to old infrastructure and long overdue repairs/replacement. But as long as nobody is "really" complaining, why not put that money out to the shareholders instead of investing into cable and a proper supply grid, right?