everything costs something

Of the more than 200,000 miles of transmission lines in the U.S., less than 3 percent are
underground.  
Significantly Higher Costs
Underground construction of transmission lines
often costs 5 to 10 times more than overhead construction.  
The lifespan of underground lines is 30 to 35 years, about half that of overhead lines.
Longer Outages
It takes an average of a week or more to locate and repair the problem, compared to a few hours for overhead lines. That’s an important reliability concern. Also, earthquakes pose the potential for a catastrophic loss,

On the San Francisco peninsula, I know two cities have had underground power lines for a long time: Palo Alto and Santa Clara.

I believe both cities operate their own independent utility districts, and purchase electrical power from PG&E among other sources.

I haven’t heard of opposition to that by environmentalists.

But no doubt conversion from overhead to underground electrical power distribution is expensive, even without opposition.

I agree with you Allen. Putting the lines underground would be the best way to go, but, the environmental wackos oppose that too. The environmental groups main mission isn’t the environment, it is the destruction of Capitalism. The sooner people realize that, the sooner real issues like putting the lines underground can be addressed.