Price will come down, quality will come up. The first VHS/Beta machines were north of $2000.00, a color printer, 1000.00. So what if a printed AR15 lower will only last a couple hundred rounds. You print off another one and swap it out.
3-D printers have been around for at least 20 years. Any of the "plastic" printers would have a catastrofic failure 1st shot, if you could get the lower to hold together for assembly.
Concentrated power is not rendered harmless by the good intentions of those who create it.
"If you find yourself in a fair fight,,,
Your tactics suck"- Unknown