On the surface the statements seems to make sense and the arguments are well put across, but unless someone actually A/B tests it and proves that it makes a difference to readership, or conversions (or whatever your goal is) then it's currently just unsubstantiated theory.
One little known tip that I've been using for years to reduce bounce rates is to increase the text size by a few pixels. I've successfully reduced the bounce rates on a few sites with that hack alone. On others it made little difference. I guess the older the audience, the more pronounced the effect.
Was this a tested hypothesis or is it literally a guess?