>Of course, bugs and disk corruption happen

And Firefox has multiple backup of sessions to the point even if your previous session was corrupted you can still recover a session saved slightly earlier. This was partly done because there are people ( like me ) who have hundreds if not thousands of Tabs opened and they ( me ) complain a lot about it.

Chrome made something similar and put in protection that may corrupt the ex-session files. To the point for nearly a decade browsers have had bullet proof session restore. ( Apart from Safari which still happens from time to time )