This is typical of old buildings that get new technology. Almost never will the old wiring / conduit be demoed when something old gets removed. Just left in place, then who ever installs the new stuff comes along and gets to add even more conduit and wire. Even to just add stuff to an existing location, you would think oh there's already conduit from A to B no problem, Probably still going to end up with new conduit ran. This kind of stuff can be anything from abandoned old analog phone lines to CCTV to even old AC power stuff occasionally.