We’re not running out of fruit, we’re just so fat and lazy from eating all the fruit we’ve already picked that we haven’t even bothered to go after the rest.
The fundamental physical resources needed to launch and land enough material for an independent colony, even on our moon, would strip Earth of the things needed to sustain us here.
There may be more fruit out there, but it's on other continents while we live on an island atol with a single tree.