Yes, that's a good point. I'm sure the knowledge half-life argument is a factor for people with PhDs, especially in academia. However, I'd be surprised if it was a big issue people at the bachelors / master's levels, and my take on the Athena report was that it was looking at S&E very broadly, i.e. people with at least a bachelor's degree.

I agree that it shouldn't be too hard to get back up to speed - after all, if it were true that (a) everyone's knowledge expires quickly, and (b) it takes forever to learn new knowledge, then people wouldn't have time to do much of anything because they'd have to sit around reading journals all day.