PG&E has a long history of negligence and stripping whatever value remains from PG&E's shareholders is an eminently appropriate penalty.

PG&E may indeed not be entirely responsible for the wild fires but it's responsible enough that this kind of penalty is warranted - ie, trimming trees around PG&E of course was something they knew they had to do and that they failed to do (just like their failure to maintain the pipe that exploded earlier).

How California deals with fire risks and utility costs going forward is complex question. Naturally, it's made more complex by the influence large corporations wield.

In this day and age, bankruptcy still offers the possibility of PG&E sidling rate-payers with its cost while maintaining shareholder value, despite this being exactly what bankruptcy is intended to avoid. Naturally, I'd like to see the state of California prevent this but I'm not holding my breath. IE, California theoretically could seize PG&E and run it as a public utility but it probably won't and thus little will change.