They talk to them and get autographs and it looks like a rock concert. I took Jacques Pepin out to Los Angeles, and people literally swooned. That's not big money, compared with top entertainers and sports figures. Salary is but part of the story, given the other money-making opportunities around. As chef profiles have grown, so have endorsement opportunities.
Some chefs do it free, just for the exposure.
And some trade product endorsements for products. Chef-owner John Hogan has been using the stuff for years. Only now he's getting it free, or deeply discounted. But never to the extent that they do now. It used to be the top three to five chefs in the world would endorse pots and utensils.