EDIT:
Luckily, weapons systems are much more effective than they were in the 1970s, so I guess we will be able to fend off the poor.
EDIT2:
Look, downvote all you want...the elephant in the room is that the rewards and advances in technology are not and can not be distributed evenly. Even in a first-world nation such as the US, so many of the products listed in my parent post are out-of-reach of anyone without significant financial means. CT scans, for example--what does imaging matter if you can't afford it?
You think that the starving huddled masses are just going to sit outside the walls and go "Man, sure wish I could live there?". That's never how history has worked out, you nitwits.