- no country pay like the US. Worked for silicon valley companies remotely, and made twice the money I made in France, while being 3 times cheaper than local competition.
- no country have the volume of hi-level coding gig job offers the US has.
- few countries even have has many interesting projects. If you want to code in Haskell or Lisp in Europe, good luck.
- the USA don't care about your diploma, only what you can do. You will be limited in opportunities and earnings depending of your background in many countries.
- talent attract talent. It's better to work with companies already full of good devs, the colleagues are coolers, the projects are more interesting and the infra will be better. Inertia is in favor of the USA.
So no, it will break no monopoly. If anything, it will make it easier to work FOR the US.