As long as we are still leaving the planet in better shape for the next generation than we found it
We are? 
Considering the millions of hectares of forest lost each year, extinguishing species, overfishing, etc, I wouldn't say so.
Destruction of forest, extinguishing species, overfishing is a result of the inability to own these resources, not resource scarcity.
In any case, if we ever figure out how to mine asteroid...a single asteroid will be more than all the building, electronics, roads, and all the other material things that's made out of lead, steel, silicon, gold, etc, combined. Gold will cease to be the storage of wealth.
Assuming our population don't grow like rabbits and our hunger for resources don't grow like rabbits, it might be the all things that we will ever need for building anything.
The next question is how do we get enough energy? Do we get it from nuclear power on earth or absorb energy from the sun?