Natural commodities like cabbage, potatoes, beans, peppers, etc are barely advertised. Generally, if it's something anyone can make and there's no good way to differentiate it, there's not much point doing much marketing. Can't speak for the OP but maybe this is what they meant?
Absolutely. These campaigns are all the products of Agriculture Marketing Boards[1] and are generally state-based. They're cooperative marketing agencies which growers and producers belong to to collectively promote their generic product. See also the USDA Agricultural Marketing Service[2].
are a few of the domestic ones I've worked with over the years.
EDIT:
Here's a list of all the official California Agricultural Marketing Programs[3]
Speaking of foreign avocados, in addition to Mexico, Chile grows and exports a lot to the US. Of of their interesting arguments is that being in the Southern Hemisphere, their crop is counter-seasonal to our domestic avos. http://avocadosfromchile.org
I've always wondered why avocados have so much marketing behind them ("Avocados from Mexico" commercials). Seems like they would be in the same boat as other natural foods. I guess it hasn't bothered me enough to do the research, though.