It means that something like the excellent annotated source reviews by Fabien Sanglard of Quake[1], Quake2[2], Q3[3], etc.. aren't possible.
Nor any ports to attempt ot make it compileable/runnable.
Code isn't supposed to be hung on a wall. If you can't even collaborate to make it work again, it does lose a lot, and waiting ~95 years isn't really a practical alternative.
Will the website stay up that long? Is archive.org allowed to preserve it?
[1] http://fabiensanglard.net/quakeSource/index.php
As long the web site stays up, everyone is free to go there and download it for himself/herself.