I think you’re making a mistake confusing rich/well-off with ultra-wealthy. For the most part, rich people do their own shopping at Whole Foods not at the discount markets in China Town. Or they do Blue Apron or whatever. Ultra-wealthy people have hired help doing their daily tasks.

For example, here in Portland there’s Grocery Outlet (stocks out-of-season/discontinued/damaged/nearly expired stuff at great prices) less than 2 blocks from a Whole Foods. I shop at both but otherwise don’t see a lot of overlap in the clientele.