The article was mostly talking about recent trends -- the first 3 of the 4 graphs began 2018, 2016, and 2019 -- and about the effects of the pandemic.
I remember there were a ton of articles back in the Obama era (when all the media did was talk about the "historically slow" recovery and the tough job market) about how the labor force participation rate of older people was way above historic norms, while that of younger workers was lagging their historic averages.
Now the articles I've seen pandemic and post-pandemic is about how the opposite is happening, and why. I don't see any evidence that hire-ability has gotten worse for older workers relative to younger workers than they were in the Obama and Slobfather eras. Actually the opposite (still a lot harder for older workers but not as bad lately), but that might just be a media meme and just anecdotal.
I don't remember there being as much slamming of the work ethic and productivity of younger generations back a decade or two before. Rather, back then, it was all about the younger people being Internet- and computer- savvy, while the older generations were in the "how do I create a file and why would I want to do that?" stage.
Now it's all about how the younger generations are on their phones and social media all the time.