Does this mean that instances that happen to have the popular communities gets hosed on hosting costs? Or stop submissions? Meanwhile "CommunityA" on other inst

Does this mean that instances that happen to have the popular communities gets hosed on hosting costs? Or stop submissions? Meanwhile "CommunityA" on other instances starve for content and subscribes. If that's true, communities should be federated as well. Like a user should be able to subscribe to "CommunityA" and get that content from all instances who have a "CommunityA". Or is that totally off?