I think this is mostly just growing up and realising that your own life is worth more than being a cog in a machine at some corporation. Not only that, but in most cases, giving 100% every single day actually doesn't matter that much for career progression, at least not within most companies. You can coast by quite smoothly.
There are certain very high-paying companies where the above doesn't apply. But they have to pay high salaries to retain staff who _do_ give 100% every day.
I think its interesting how takes like this are always stated so matter-of-factly. Growing up, inevitable maturation, leads to the discovery of individualism and the desire for something more than being a cog in a machine.
I believe, strongly, that this reverses the cause and effect. No one wants to be a cog in a dysfunctional machine; and the sheer density of dysfunctional machines in our society has induced a renaissance of individualism. Its a reasonable response; you can't trust the machine to reliably arrive at the correct outcomes, but you can trust yourself.
The biggest reason why I believe so strongly that this cause and effect is reversed correlates toward human nature, which has always angled toward social organization. Some philosophers would argue that there's nothing more fulfilling than being a part of an organization larger than the individual; taking any form from marriage and starting a family, to organized religion, government service, or capitalistic corporations.
Individualism isn't a symptom of maturity; its a symptom of systemic dysfunction.
There are certain very high-paying companies where the above doesn't apply. But they have to pay high salaries to retain staff who _do_ give 100% every day.