I would prefer that this become the standard for software, as a whole, to be open source after a while. Because there is a sustainability aspect, just like the rest of the tools in our world.<p>For example, a manual drill has no real draw backs it will always run. An electric drill with a cord, will likely always run and electrical components can be traced and sourced rather easily. A drill that was designed to use with a battery, will not always run, and has software/firmware with some other limitations likely buried in the software.<p>The moment support is dropped, it should be released to open source to allow others interested to maintain it. Such as with the Nvidia Geforce GTX 1080 Ti... no longer supported with driver updates (outside of "security updates"). The firmware should be supported by the people if the company doesn't want to support it, it still is an excellent card even 10 years later...<p>MMO or not, source code should just be released. Patents are not forever, source code shouldn't be either. Though patent might be too long as well. 15/20 years worked when things developed slowly, but now days its outdated within years and could benefit other advancements.
If a company is willing to continue maintaining a piece of code their monopoly should continue. If they choose to stop (because they can't come up with a sustainable business model, can't find somebody to sell the monopoly to who will, etc) it should become, at minimum, source available (if not out right Open Source).<p>This should be the case, especially, for software that drives long-lived hardware devices in infrastructure roles (public works, manufacturing, etc).