Another thing happening is that a lot of U.S. companies are "friendshoring" to Canada, India, Australia, and Europe, where salaries, in real terms, are somewhere between 25%-50% cheaper for what is effectively the same productivity.

Anecdotally, it appears to be boomtime right now in at least some Canadian tech hubs.

My best guess is that this is being driven by three factors: The collapse of the SV ZIRP bubble, the animus with China, and the exceedingly strong US dollar.