And they continued to pay their US based employees more (including employees relocating from cheaper locales) because CEOs believed (whether rightly or wrongly is irrelevant) that there was a significant advantage to having them physically collocated with their teams in the US.
Essentially, US workers have spent the last 2 years screaming at CEOs that no, they’re idiots, there is absolutely no benefit to physically collocating employees in the US and they should not have paid them anymore.