> Like....what licencing issues? After the game is "dead" and the parent company doesn't want to support it anymore, we could easily release the source code or even just the executables for the servers.

I can't speak to the parent's stance, but more generally this would be referring to IP licensing and patent encumbrance. I've worked on a number of large systems where non-trivial parts of the codebase were licensed from external parties with distribution restrictions in place. Even the executable versions would be problematic as the contracts go to great lengths to lock it down to strictly company XYZ may modify and use the IP, but nothing else regardless of the form or means of distribution.

Releasing said systems as-is would require either relicensing to allow distribution (very costly and potentially impossible if the vendor declines), or replacing that functionality with a cleanroom implementation. Which is both costly, time consuming and difficult. You may also run into further issues there if the contract forbids cloning functionality, or even worse: if there is patent encumbrance you have to go back to the relicensing option.