Not where I come from (rural Northern California).

We were pretty much lower middle class (sometimes lower-lower) , had friends who were better off and friends who were much worse off, and nobody really talked about money openly.

In my family I always figured it was WASP reticence, but now that you mention it I think it was something broader. Maybe: people with money don't need to talk about it, people without money are embarrassed to talk about it, and if you're somewhere in the middle you don't want to reveal your hand.