There's no need to argue the assumption. There are more than enough resources in this solar system to satisfy a few trillion people. The atoms that make up that cheese burger have been a billion different things. Leeching energy out of the enormous energy surplus raining down on us is the easy part. Developing the positional-chemistry needed for mature nanotech is the Holy Grail. This has already been done with femto-second lasers tweaked by genetic algorithms used to shape the waveform to steer chemical reactions in preferred directions.
I have to laugh at doomsayers who claim man is so vile and corrupt that nothing good can come of him. I see the ratio of time it takes to create vs the time it takes to destroy is like 1000:1 and despite that civilization advances. How could this be unless the ratio of people being constructive was more than 1000 times greater than the number of people being destructive?