I watched a video on this proposal, and one interesting argument is that this isn't even supposed to be necessary, since leaving a game broken that you paid for is a violation of your property rights. Any (armchair) lawyer wants to opine what the courts would think of this?
The initial direction of the campaign was to investigate whether or not this was legal at all. The short version is - they refuse to answer and sidestep the question.
They answer the questions to their ability and their purpose. They are not courts and are thus not finders of fact. If you phrase a question that would get them to act as one then their correct course of action is to simply state which relevant law governs that.
One problem I have with Ross and his lawyers is his lack of reaction to the initial answers form the comission. The digital content and services law talk about objective and subjective conformity and the commission emphasized this: why didn't they use that terminology? The purchase of a game itself is a purchase of digital content (you purchase access to data in digital form) while running the servers is undeniably a digital service. So the game is in essence a bit of both. That is fine and desirable.
It is obvious that eliminating the service makes the game unplayable and being able to play the game without reverse engineering is undeniably the most basic objective criteria a game has: that you can play it. The primary remedy is to make it conformant. The minimal action that would objectively make it playable would be the ability to point the game at a different server. The fact that no service currently exists is a semi-related criteria. Subjectively, they probably also need to provide some way for people to sensibly build servers, although maybe this is an objective requirement: the requirement that a game requiring servers has a way for users to ensure that a server is running. Otherwise, vaporware companies could build "games" that require connection to a server that they never build and if you have the misfortune of buying one you somehow got what you expected--an unplayable game? Publishing the server with the game (like many games do) is the easiest way to do this, although perhaps publishing an API is enough if they are extremely upfront about that?
The secondary remedy is refund and the requirement is that they refund the difference in value between the current value of the non-conformant digital goods and the value if it was conformant. This one is obvious, since in its nonconformant state the game has no value. So the refund should be full. This is the remedy that may make free-to-play games more attractive to certain predatory businesses that want to terminate games despite the investment of time and money by players like Ubisoft here.
This is the legal theory that you need to present but this theory is clear from the law so I don't know exactly what more you would need from the commission. In principle, anyone could reach out to Ubisoft (or Steam if you purchased it there) and present this theory stating that you purchased digital content which is no longer objectively conformant due to their changes. From there they need to tell you if they will create a remedy so that the goods function again, failing that they can refund you. If you get no response (possibly they attempt to dodge the law by stating you purchased a license, but the EU clarified that isn't relevant since it was a license to digital content and thus this law comes into play) or they clearly are giving you a run-around you can demand a refund and they have 2 weeks to comply. The law also empowers you to seek remedies outside of the courts so chargebacks are conformant to the intentions of the law at that point in time. Moreover, the law prevents the company from retaliating against you for asserting your rights. Getting your money back is the consolation prize, since I imagine you just want to continue playing the game that you love.
I have multiple times sought remedies under this act so I have read quite a bit about it. I have read quite a bit about it and have been lucky enough to receive remedies without needing to go to court so far. I am not a lawyer, just an autodidactic citizen.
My personal opinion is that an always-online game isn't even your property. No more so than an account here on Hacker News has me own HN/Ycombinator. It's their server and if it shuts down tomorrow that's unfortunate. But perfectly within their rights as handling their property.
In a casual legal sense, I feel it will ultimately come down to how and what a court considers a good, and how much of a digital good you own. I can see an alternative argument in a case where, say, you end up buying a "new" game at WalMart for a server that is no longer up. In that extreme case I can understand feeling like you were swindled (I can't think of a case where this happened, but I wouldn't be surprised about this occurance). So I can understand an argument where there should be some sense of game you buy when you buy a game.
Is it a property though? You are buying a non-exclusive revocable license for specific piece of software, it's not an NFT. You don't own anything, you only get permission to use thing you paid for in a set of specific circumstances. Usually it is written somewhere in the license agreement.