No, this is what happens when employers show their workers absolutely no loyalty over decades. If people have no reason to care about their job, they won't care about it. The labor market is tight enough so that they can't just fire everyone who behaves like that, otherwise everyone would quit.
That’s a factor, but the collective dumbing down is as well. We now have a nearly feral workforce and body politic, because contrary to expectations, they’re unpredictable and hard to control.
Graduation rates are are higher than ever. Over 30% of people have Bachelors degrees or higher. Literacy rates are higher than they ever have been.
Our people aren't dumber, they just realize that when the business managers and owners are making millions while they don't get wage increases above inflation, they have no incentive to care.