It's kinda neat how they are sending disk/block-level reads and writes, probably using a user-space/local HFS file system implementation, to inject the exploit, since the mounted file system is read-only.
A few of those are created by the jailbreak but most are core parts of the system.
It doesn't seem like it'd be incredibly hard to remove those symlinks. Although Apple would probably favor fixing the bugs that allow malicious symlinks rather than remove symlinks from their file system driver (the horror!)
Plus, old binaries break all the time due to incompatible software or hardware changes (AVFoundation, GL shaders, UDID bans, etc.).
And new builds certainly get new requirements imposed (forced minimum SDK version etc)