This would be an issue if the servers use any proprietary code, libraries, or services the developer is not at liberty to distribute.
A studio may also to reuse their networking code for a sequel, and it would suck being forced to release that just because an older title got discontinued - could lead to exploits, or just competitors profiting off of your hard work with no compensation in exchange.
That sounds like a nightmare! I don’t think game developers (or any other artist) would want the CRA breathing down their neck, telling them what they can or can’t do with their work. I certainly wouldn’t program under those conditions.