>>7
"General-purpose material synthesis techniques" huh? Yeah that's called alchemy. We tried that in the middle ages and it didn't work so well.
And the fact that recycling can get back used raw materials doesn't change the fact that meteors contain nothing useful. That 10^8kg of material the earth gains everyday doesn't matter. Even if we do reach some magical point where we can efficiently turn dirt into platinum, I think we've got plenty of that stuff lying around without meteors refilling our supply.