Based on talking to my coworkers from Europe on the West Coast (some have more nuanced position, but some were outright "everyone in tech in their right mind moves away from Europe"), nothing short-term.
If you forget specifics, and consider on the abstract level what the differences are... Let's say there was an equal pile of "resources" per person available in Europe and the US. The way this pile is (abstractly) distributed in Europe is egalitarian and safety-net focused; in the US it is distributed more unequally, closer to some imperfect approximation of merit. Most of the (real) advantages and disadvantages that people bring up for the US stem from that. The more of this approximation of merit you have, the more "resources" you'd have in US. No matter what the specific slopes are, unless one place is much richer (might be the US anyway), at some point these lines cross. The higher the person is above this point the more it makes sense for them to go to the US...
There are also 2nd order effects like other people above that point having already gone (not just from Europe, from everywhere in the world), making the US more attractive, probably. That might matter more for top talent.
And although this probably doesn't matter for the top talent, "regular" Europeans can actually have the cake and eat it too - make the money in the US, then (in old age or if something happens) move back home and avail themselves of the welfare state. A non-German guy who worked in Germany for a few years told me that's what he'd do if he was German - working in Germany sucks, but being lazy in Germany is wonderful, so he'd move to the US then move back ;)
If you forget specifics, and consider on the abstract level what the differences are... Let's say there was an equal pile of "resources" per person available in Europe and the US. The way this pile is (abstractly) distributed in Europe is egalitarian and safety-net focused; in the US it is distributed more unequally, closer to some imperfect approximation of merit. Most of the (real) advantages and disadvantages that people bring up for the US stem from that. The more of this approximation of merit you have, the more "resources" you'd have in US. No matter what the specific slopes are, unless one place is much richer (might be the US anyway), at some point these lines cross. The higher the person is above this point the more it makes sense for them to go to the US...
There are also 2nd order effects like other people above that point having already gone (not just from Europe, from everywhere in the world), making the US more attractive, probably. That might matter more for top talent.
And although this probably doesn't matter for the top talent, "regular" Europeans can actually have the cake and eat it too - make the money in the US, then (in old age or if something happens) move back home and avail themselves of the welfare state. A non-German guy who worked in Germany for a few years told me that's what he'd do if he was German - working in Germany sucks, but being lazy in Germany is wonderful, so he'd move to the US then move back ;)