Now that you mention it, the setup I imagined is dang near identical to an SEM, but with atoms. All we need to do is replace the filament with a mass spectromet

Now that you mention it, the setup I imagined is dang near identical to an SEM, but with atoms. All we need to do is replace the filament with a mass spectrometer's filter and bam! Instant micro-3D printer (where instant is ten-twenty years of R&D :). I'd be willing to devote a decade of my life working on that. As for the second half, I apologize. I didn't realize you were thinking in terms of the long now. I think you're completely correct: we will spend the time and effort to make it better and faster. I have no doubt industry will come through for us in this. We got to supercomputers in our pockets in less than one lifetime, after all!