That implies the community that builds around it would not reverse engineer and remake the binaries. Which many already do (to be fair), it just so happens that it's way, way harder when the servers are entirely gone already for a game and you have no way to capture server/client traffic for example. Even if the binaries are flawed, just having those in there and being able to spin up a server to see the packet flow already greatly helps in preservation, much more if you have the binary itself and can also peek at server logic for certain things like conflict resolution, instead of having to guess post-game-shutdown!