I just find that more disappointing because the copyright holder is positioned to be able to open-source or public-domain-dedicate the material but they don't for various reasons and it rots on a backup drive somewhere or gets lost, and now unnecessary duplication of effort must occur to recreate it.
Often it seems rather paradoxical in nature because the main reason they don't open-source it is that they're waiting for a time in the future when the demand rises and it will be worth something again, and yet the increased demand only happens because of the efforts of reverse engineers keeping the community alive. It's almost always impossible for the reverse engineers to legally get paid for this work too. The only hopes for that is either for the copyright holders to raise enough money and decide to hire them, or to do an anonymous patreon and hope it doesn't attract the wrong kind of attention.
