Because listening to someone selling tea is not engaging radio. He's got enough obscene profit breaks as it is. I tune in to radio to be entertained, not to listen to sales pitches for tea. I make my own tea. It's not that tough to do.
Lord deliver us from a wealthy housewife who wants to launch a vanity project. Mail order tea sounds as unwieldy as streaming video over a dial-up link.
I can make my own mayo as well, tastes just like Hellmann’s. I prefer to buy it instead of making it.
I tune in to radio to get informed. If you want to be entertained, find another avenue.
Rush, other than being informative, also has a great sense of humor, sometimes to subtle for those who have none.