Let's say you corrupted one bit in a blender asset 200 revisions ago and it was unnoticeable and still upgraded through five blender upgrades, but now on the sixth upgrade it fails with a corruption error and doesn't upgrade.
Without knowing how to fix that error you've lost 200 revisions of work. You can go back and find which revision had the problem, go before that, and upgrade it to the latest blender, but all your 200 revisions were made on other versions that you can't backport.