PG&E would love to spend more money on maintenance. It doesn't cut into their profits, because their expenses and profits are set by state government commission anyway. Of course, the government commission has some incentive to keep the rate low, to make citizens happy, which makes it limit how much money PG&E can make and spend.
The above is not meant to imply that if PG&E worked like any normal company, they'd maintain their shit better -- I have no idea if they would. However, in the current regime, where CPUC exercises so much control over what PG&E does and how much money it makes and spends, the blame cannot be solely placed on PG&E side.