We really need a law for that. They should have to either

• buy them back
• make sure they work for a sufficiently long time after the last unit was sold (e.g. 5 years)
• make the software open source so the community can maintain the software (if even possible, cause the community won’t be able to work on the server side)
• release an offline patch that makes the device work even after servers have been shut down if that makes sense for the device in question (applies mostly to always-online single player games)