Interesting question. I guess that humans will not use up all natural resources, because the restriction of freedom (already) applied to ourselves will yield an equal limitation to the resources available to all. Hence the bell-curve of access to resources will become more concentrated (than it already is) commensurate with fewer people controlling the oligarchy that provides access. As a result of population growth putting severe pressure on access, wars will ensue in which we kill ourselves way before we run out of resources.
Such is the outcome of the manmade operating-systems we have built, in direct conflict with our best understanding of the operating-systems of nature, designed for optimal evolution. No escapism to Mars will provide respite here.
Luckily we can fix our manmade operating systems, and I cannot imagine a more imminent problem than precisely the one I am addressing right now.