Spoken like someone who hasn't actually looked at the stats. Science is a power law game. It is not about the total headcount moving; it is about the top 5 percent moving. If the top 10,000 PhDs, the ones landing the major grants and patenting the next gen tech, decide that a lower salary is worth the trade off for actual stability, the US loses its competitive edge.
The financial suicide argument falls apart once you look past the raw dollar figure. Subtract the 50,000 dollar private school tuition, the 20,000 dollar health insurance premiums, and the 4,000 dollar monthly mortgage for a 110 square meter house in a US tech hub. The math shifts quickly. Germany, for example, is consistently 30 to 40 percent cheaper across the board.
The zero buy-in claim is also factually wrong. The US has bilateral totalisation agreements with the UK and most of the EU, including Germany, France, and Italy. You don't lose your credits; you combine them. You can work in Berlin for ten years and those years count toward your US Social Security retirement threshold, and vice versa. It is not a vacuum; it is a coordinated global system.
Beyond the money, there is the quality of life reality. The US currently ranks 38th globally in quality of life, trailing well behind the European nations you dismissed. We are talking about a 4 year gap in life expectancy. In the EU, your kids get a world class education and a functioning social safety net without needing a 401k to survive a single medical emergency or a car crash - the latter of which you are six times more likely to die from in the US than in the UK.
You claim the EU lacks infrastructure, but they have the one thing the US is currently hemorrhaging: predictability. Researchers are trading big funding for public funding that does not evaporate every time a continuing resolution fails or a political cycle turns.