It would take a ton of bureaucratic overhead, but you could have a system where you could apply for permanent ownership of a domain only after establishing that you're actively using that domain for the purpose of a business or project. Basically a trademark system for domain names. Perhaps with the caveat that a limited number of domains could be reserved for any one project, so that Google couldn't tie a thousand different URLs to Blogspot.

I'm very unhappy with the impermanence of online resources; some great websites that I used to rely on for information or conversation have just disappeared with time. Some have been archived by the Wayback Machine, some haven't. Obviously, a permanent server is a bigger concern (and a bigger problem) than a permanent domain, but I still think something like this could be a step in the right direction.