If one small part of the mobile is touched, all other parts of the mobile will be affected. People who accept the steady-state paradigm believe that humans are now at a point in their technological development where they have to give up the belief that there are frontiers where one can find new wealth and opportunities. Humanity can no longer afford the luxury of imagining the earth as being incredibly large, plentiful, and dangerous. The simple and obvious fact that the earth is limited in size is a new challenge for humankind. It means that people will have to decide how they can ethically make trade-offs between all the different demands on the world's limited resources.
Land is obviously a limited resource.
It will take a large investment to create more land capable of producing food. Much of this land will be taken at the expense of other uses and of creatures who depend on it. The sea is another limited resource. Its ability to provide more and more food is limited. Fish catches have been declining and will continue to decline until overfishing stops.