Asking for additional development work on a game that is being shutdown obviously won't work, as that that amount of time spent on a dead product is just a waste of money for the business. For example, asking the company to dockerizing the server software, or split their code from the licensed third party tools like speedtree, RAD Game tools, etc and release it open open-source just wont work.
However, I do think most companies could justify asking one of their developers to spend just a single hour to document/copy+paste the _bare basics_ of the network logic for the good PR alone.
They could literally copy+paste their network serialization logic (whether it's something high level like protobuf, or just a raw C++ enum for associating the packet ID's with descriptive names). That's it. Just that one thing alone would immediately raise my opinion of any company that has to shut down an online game service. Just that single thing alone would save their fanbase hours of time spent on reverse engineering the networking for server emulator development.