I'm interested what would cause underground cables to break more often. Is it people not "calling before you dig" and accidentally severing them or is it something else?
Throw in backhoes, erosion, etc. along with it being more expensive to fix when it does break, and overall it isn’t always guaranteed buried will be cheaper maintenance wise.
I don't know what PG&E will use in this case, but all buried power and transmission lines lines are robust against water infiltration. Solid-dielectric cables are rated for direct burial, and cooled lines are encased in steel conduit. Both types are sometimes further protected in concrete.
There's always another rat (or squirrel, or rabbit, or mole, or ...)
Growing up, this was something that occurred multiple times a year. Squirrels would climb the poles and short themselves across the 2 leads on the transformer. Zap, one less squirrel, and several hours without power while the power company came out to diagnose the problem and then send out for a replacement.
Independent vendors are faster, cheaper, and offer a more locally-adapted product.
The squirrels seemed to replace themselves without servicing. If only the transformers were capable of the same thing.