[Beermotor]

Ok so that answers the age question: a study found fluid intelligence starts to decline the 60s and 70s.

I think OP's article is talking about people between the ages of 35 and 60 not being able to see ads.

What is more likely is that more experienced workers have higher salary requirements and are less likely to work 90 hours a week.

[itsybitsyspider]

Those studies don't necessarily give you a definite answer regarding age. Other studies suggest that it starts much earlier: http://www.sciencedirect.com/science/article/pii/00016918679...

Salary and work-life balance expectations definitely play a huge role in this phenomena - I'm just pointing out that there might be other factors too - factors that people often reject up front because they feel uncomfortable with them.