If you ever need to lawyer up against a company it would be very wise to have your lawyer do “discovery” on any email any manager has written about you. This should be standard advice to all employees.
It's wild that this continual destruction of evidence is not only tolerated but SOP. It's just so convenient! Imagine if commit messages disappeared after 6mo!
There is probably a desire to make commit messages go away after 6 months. I am guessing that the lawyers aren't putting much pressure on engineering teams because nobody has thought to "discover" commit messages in a major case yet (whereas email is routine).
Well, the alternative is for every last written thing at a company--jokes, gripes, mistakes--to be scrutinized and taken out of context in court by an opposing side's legal team.