When I compare today's salaries with what developers were paid in the 90s, I don't get that impression. Salaries keep going up.

Yep. Thats why recruiters/employers are so desperate to fill jobs. That's why governments (pushed by big tech) are trying to teach toddlers how to code. That's why 200k+ salaries for senior positions are now pretty common.

I cant think of any objective reason this would be true. Salaries are going up and our influence in the world is just going up. Through covid our value seems to have gone up even more actually.

the whole field's expanded; the average pay is lower because there is so much janitorial work to be done, but the high end has exploded.

Nope. Quite the opposite actually.

1) That's not true. There's a narrative outside the field that it can be outsourced, even VCs have "sagely" told me that, but it's a lay person misunderstanding. (Ironically, very little semi hardware is done in US startups, so that leaves only software.)

2) US companies keep ratcheting up interview demands, which artificially constrains eligible candidates.

Examples are using coderpad where your code has to compile and pass a test/performance suite now, and doing random memory quizzes in addition to programming. But that's the fault of the hiring company.