My understanding is that they could not, yes, because state regulators exercise line-by-line control over PG&E's budgets, including how much money will be distributed as dividends and how much money will be spent on maintenance.
PG&E could easily fix the lines and pass the price onto the consumers. If anything, if their profits are limited to 10%, you'd think there would exist a perverse cost+ incentive on PG&E's part.
[1] https://www.macrotrends.net/stocks/charts/PCG/pacific-gas-el...
Keep in mind that even if PG&E is doing their best to keep costs low, the cost of wildfires is being passed on to the consumer anyway (in some cases the cost is being passed on as dead humans instead of higher electrical costs). Is it better for PG&E to be able to have a profit margin of 25%, or for their lines to not cause wildfires? What about a low profit margin stops them from maintaining lines?
If the state and/or counties are operating the electrical company, profit need no longer be an issue. If they aren't making enough money to cover maintenance cost, that can come out of tax dollars or state-issued bonds just like road maintenance does. It's not as if electrical infrastructure isn't important. Taxpayers may not like higher taxes, but they also don't like having their power cut off or their houses destroyed.