The prevention mechanism is fairly obvious, and it's to rank the H1 applications by salary instead of the current lottery system. Genuine employers like Google or Facebook don't need to game the system, it's the outsourcing shops employ this tactic to boost the margins. They're welcome to join the game by boosting their salaries, though.
From the US government point of view a US salary paid in the US is a net win over a salary paid in Ireland or Switzerland, as it's still subject to federal income taxes, so net win on revenue.
With the current administration, their priority was totally upside down.
> I have no idea.
Also, respectfully, I think that you should have an idea how things are likely to effect you before you form a preference for one alternative over another.