In terms of resources, ultimately if is just a function of energy. And of course technology.
If you have enough cheap energy, then you can: divert rivers, mine the bottom of the seas or the asteroids, and synthesise plastics and even biomass to order. In our future, unless we stuff it up and go back to wearing hair shirts and lving in caves as the enviro-totalitarians want, we may well be able to shove garbage and refuse into Mr Fusion to get Gigawatts on tap. Extrapolating, we may well dial in Mr Fusion to synthesize food, plastics out of our waste, and even metals and other industrial materials from more common elements. It's just a realignment of a few protons and electrons really - pretty elemental really