While everyone should sign it, the campaign is about publishers that kill games that could conceivably remain working.

De-listing is likely a result of expired licensing or similar, and I don’t think it’s feasible (or realistic) to require companies to renew licenses in perpetuity just to keep selling games.

While I agree with the sentiment: It won't be killed, "just" de-listed from sale. If you buy it now, you can still p/ay it.

Although an end-of-life plan would probably make it easier for the publishers to still sell the game after licences expire.