Fun (or sad) fact: they apparently lost a lot of the source code and assets. Looks like they were able to recover most of the code, but not the assets [1]
[1] https://www.gamespot.com/articles/how-diablo-2-was-almost-lo...
[1] https://www.gamespot.com/articles/how-diablo-2-was-almost-lo...
I think the only thing they really lost are the hi-def assets from which the lower-def ingame assets were created.
I can't think of any other way of interpreting it.