Federation already solves this, mostly. If kbin.social disappeared, other places like kbin.cafe and kbin.lol would have copies of the magazines, so content wouldn't be lost. And the community could regroup under a new magazine.
The only issue is magazine portability - right now there doesn't seem to be a way to annoint an instance to be the new owner of a magazine that's hosted by the kbin.social instance. But maybe that technical problem will be solved in within the next five years.