Where do you get your "facts"?
You wrote: " there are roughly 700,000 shoulder firing missiles out there, unaccounted for."
Really? Where did that silly number come from?
The total number ever produced is somewhere about 100,000.
Most of those are no longer functional, having been made in the 1970s and 1980s.
Of those that remain, the US, Russia and other reasonably respectable governments have about 99% fully accounted for.
This leaves perhaps a thousand, of which a few hundred may actually work.
David F Mayer