Exactly. Time machine is for those "oh shit, my disk is toast/I really didn't mean to delete those files/I'm switching to a new mac" moments. It's not intended

Exactly. Time machine is for those "oh shit, my disk is toast/I really didn't mean to delete those files/I'm switching to a new mac" moments. It's not intended to be used to retain a complete history of your machine and as such if used for this purpose you're eventually going to get a nasty surprise.