We need lots more power lines. Why are we so bad at planning them?

Electricity transmission in the US is privatized and handled by several hundred individual companies [1].

These associate into regional councils that are obviously regional in focus. The NERC, the North American Electric Reliability Corporation sets standards for these councils.

Barring any large-scale government initiative, all planning is from the bottom-up, so that's why we're so bad at planning in the large.

[1] https://www.nerc.net/eroregistration/currentmembers.aspx