Just over the last 6-9 months, salaries have markedly jumped.
There's still a huge thirst for talent that isn't being quenched, and global pools don't help either.
Facebook, Google and others have satellite offices all over to soak up talent elsewhere, but they're still ultra competitive in the US.
They can pay a senior engineer $350k in the US, or an equivalent experience senior engineer $100k in Europe. There is no shift occurring though. They're still hiring like crazy everywhere.
There's no place like the US for tech workers. Nowhere even comes close, even on a CoL-adjusted basis. European developers get screwed. South American developers get screwed. Asian developers get screwed. US developers don't get screwed.