Just thinking about every point in my life where I ended up in "who cares?" was due to concerns outside of my control/power. When I feel I have some agency, power, and/or recognition it just naturally follows that I will care (in varying degree but I will care somehow); even if not for the larger organisation I will care about my immediate peers/team.
If I'm not paid enough, or I don't have agency, or I don't feel heard and my point is proven later (multiple times), or a superior is an asshole, so on and so forth, I naturally end up in "who cares?" after some beating.
Of course, it's all personal experience/anecdotal evidence, but in general I don't think most people just turned the "who cares?" mode on and wage stagnation followed, it seems to be much rather the opposite, you take away safety, money, agency, and any other aspect that might make a job more fulfilling and the only natural progression is people disengaging from the activity.