We'll probably never have evidence either way ... Did Google and Stack Overflow "replace" programmers?
Yes, in the sense that I suspect that with the strict counterfactual -- taking them AWAY -- you would have to hire 21 people instead of 20, or 25 instead of 20, to do the same job.
So strictly speaking, you could fire a bunch of people with the new tools.
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But in the same period, the industry expanded rapidly, and programmer salaries INCREASED
So we didn't really notice or lament the change
I expect that pretty much the same thing will happen. (There will also be some thresholds crossed, producing qualitative changes. e.g. Programmer CEOs became much more common in the 2010's than in the 1990's.)
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I think you can argue that some portion of the industry "got dumber" with Google/Stack Overflow too. Higher level languages and tech enabled that.
Sometimes we never learn the underlying concepts, and spin our wheels on the surface
Bad JavaScript ate our CPUs, and made the fans spin. Previous generations would never write code like that, because they didn't have the tools to, and the hardware wouldn't tolerate it. (They also wrote a lot of memory safety bugs we're still cleaning up, e.g. in the Expat XML parser)
If I reflect deeply, I don't know a bunch of things that earlier generations did, though hopefully I know some new things :-P