I try to say this gently, but this comment would make more sense if it came from lots of direct experience, rather than (what appear to be) repeated tropes. Have you seen this repeated in your own over-40 experience or the experience of people you know?
Likewise. I hit 40, which I didn't think was that old, dropped out of contracting and found employed work has gone from being easy to, well, IME impossible to turn up.
I've seen it a few times. One company replaced the entire QA department with off shore people from India, this didn't go well. Another replaced a bunch of devs with off shore people in Belarus, this did go well.
This happens, that much is unarguable. But replacing departments does not disproportionately affect workers over 40 unless that dept is disproportionately over 40, which begs the original question: How can one find such a dept!?