Also your notion of "better tools" may of not happened, or happened more slowly without open source, AI, etc which would of meant higher salaries for longer most probably. That's where I disagree with the parent poster's claim of higher salaries - AI seems to be a great recent example of "better tools" disrupting the premium SWE's enjoy rather than improving their salaries. Whether that's fair or not is a different debate.
I was just doubting the notion of the parent comment that "open source software" and "automated testing" create higher salaries. Usually efficiency economically (some exceptional cases) creates lower salaries for the people who are made more efficient all else being equal - and the value shifts from them to either consumers or employers.