I agree with this interpretation. Plus, I don't think it generalizes that well. In my stomping grounds, there are three circles of trust where people tend to talk about different things:

- Outer circle: the weather, dead relatives (yes, dead relatives!) and "expensive vs cheap" but without actual figures.

- Middle circle: what to eat, where to travel.

- Inner intimacy circle (people who are okay sharing a bed): money with actual figures. But you may not discuss the salary.

Celebrities don't show up in any of the circles, because one needs a measure of lightheartedness and humor to deal with that topic and use it on gossip about somebody else... which is a combination not everybody can or want to manage...not sure if that's a good or a bad thing, but it is what it is.