the math changed because they were sued for something that should've been acceptable risk. So now it's unacceptable risk. What goes around, comes around.
They didn't wind-up liable because arcing electricity just happens to sometimes 'cause fire.
They wound-up liable because they gutted their tree-trimming operations and paid the difference in dividends. That is something that definitely makes you liable regardless of whether the original thing is an acceptable risk.
Now, it's hard to if this is indeed a "bail us out or we'll shut down at every strong breeze" statement or whether they are legitimately worried the lines they neglected actually now ignite at every strong breeze.
Either way, I think the average Californian justifiably hates this company. But it seems unlikely things will change.
The Camp Fire, which is the one that looks likely to bankrupt them, probably wasn't even caused by inadequate tree trimming. Apparently one of their power lines had a weak, defective fixing which failed due to the same high winds that caused the fire to spread so rapidly and uncontrollably.
Uh, it seems obvious that the question is not tree trimming in particular but maintenance generally. The gas explosion the killed thirty people might hypothetically have been just an accident but logic, rules-of-thumb and actual evidence available all pointed to it being a problem of inadequate PG&E maintenance. Assuming the cause was a defective power line, maybe it was totally an accident but it seems unlikely in the scheme of things - most likely it was part of their pattern of negligence.
Edit: Note, the Camp Fire has bankrupted them. They are bankrupt, in bankruptcy proceedings. They are also on criminal (not civil) probation. None of this stopped their stock from rising after the recent events - where a more naive me might expect their stock holders' money would be forfeit once they reached the level of bankruptcy (unsecured debtors and all).
Decades of pretending that liability didn't exist just caught up with them.