Capitalism didn't bring scarcity into being and communism won't end it. It might be better at distributing resources equitably and preserving them longer, but the physical reality of the universe is that there's e.g. only so much grain you can get out of the ground every year and so many years at a certain level of production that the soil can sustain, so much land to be cleared for agriculture etc. The Earth is functionally a closed system and as much as communism might allow for technology enabling its matter to remain in a state useful for human social reproduction for far longer than under a capitalist mode of production, there's no solution to physical phenomena being fundamentally irreversible reactions. Even if we were to expand the reach of our species to the stars, that's still just kicking the can really far down the road.