To answer the question, see cageface’s comment.
I can't speak for others, but here are a few reasons I would never move to the US for work. Note that I visited the US multiple times (alas in the 90s) so I'm aware that it's a very diverse country with very diverse (and usually incredibly nice) people and it's not the usual anti-US reflexes that would keep me from working there, ever.
Let's begin with the fact that you don't get any vacation by law. Some companies will not even provide you with sick days, which is a completely absurd from a European perspective
Let's continue with the fact that employment laws in most states are extremely pro-business and very much anti employee. Agreements like mandatory arbitration and no right to an impartial judge in case of disputes would be laughed out of any European court. At least it would be laughed out of any court in Switzerland, which has one of the most liberal and lenient employment laws in Europe.
Let's continue with things that would be simply extremely uncomfortable for me. While I'm aware that not every American is armed to the teeth there are enough people packing heat, especially in southern states. With measures on the way to allow a carrier of a concealed gun to carry it throughout any state makes me extremely uncomfortable and I really don't want to live in such a society.
We could continue with cities which are basically designed for cars, not walkable, not pedestrian and bike friendly and with horrendous public transport options. Sure, there are an excpetions (actually I can only think of New York from the cities I know). I don't want to live in a city where I'm either dependent on a car or on the likes of Uber.
You imply that money is the main motivator. It's not to me. As long as I have a satisfying job and make enough money to cover my daily needs (and maybe allows me to order a craft beer instead of the general swill without having to think about it) I'm more than happy. I make enough money to have no debts, being able to afford my travels (to Japan in April for a month) and if I can afford those things that make life a pleasure to live I'm happy enough.
Too each his own, I guess. But I vehemently disagree with your premise that money is the main motivator for going to work.