You don't need a Phd or a lot of money to have a skill that an American doesn't have. Assuming that those things are 'indicators' doesn't seem to be based on anything.
The difference here is that America has a large 'labour' pool, but the roles you need filled aren't as much just clocking in and out doing some random task, but have requirements that are harder to meet and apparently aren't met by the available Americans. Assuming malice isn't very constructive and to do something about it that actually helps anything needs some backing information.
The other way around: most people don't really want to work in the USA and will only go if the money is right. This also means that the company in the USA that is trying to find someone to fill a gap in their needs might have to spend twice as much getting their problem solved. At the same time, the amount of Americans asked to work outside of the USA is rather low as there aren't that many special skilled people that aren't already available. If you check out the sources listed at the WikiPedia page at https://en.wikipedia.org/wiki/American_diaspora you'll find that a lot of emigration happens for other reasons, and only a small part is related to special skills needed in emerging markets (which are markets that need a lot of skilled people but are not very attractive to a lot of people due to cultural differences or stability worries).