If the goal is to keep US employers competitive by letting them hire the best and brightest workers from around the world, doubling employee compensation costs

If the goal is to keep US employers competitive by letting them hire the best and brightest workers from around the world, doubling employee compensation costs is probably not going to achieve that - the companies will just open foreign offices. Which is already happening due to uncertainty of the entire program, my company shifted from opening a USA branch office to opening an european office to make it easier to hire european workers. And it's not like we're using H1-B's as cheap labor, all of our H1-B's are PhD's (well, maybe a few Master's degrees in the mix that have significant experience), and are well compensated. We have a strong USA college recruitment program too.