Replace people with machines and especially those that have been there the longest who are getting paid more.
This has been going on since the Industrial Revolution began, eh?
. . . and especially those that have been there the longest who are getting paid more.
But accelerated when decision-making logical chips were coupled with arithmetic and/or precision-measuring instrumentation. Are not people grouped by more tine-in-grade experience expected to be more universal and faster in tasks?
Unions rested on postulated seniority-related superiority, not on statistics-related individual meritocracy. Eventually, a very great failure in presuppositions, and suicidal in no-holds-barred competition.