Restaurants often do get first-pick, but it's probably just because the producers or distributors can make more money selling to them rather than the grocery store. I.e. just another feature of capitalism. This happens with a lot of things, such as home builders and furniture makers getting first-pick on lumber. Now that I think back to when I used to work in fabrication, steel as well.

For high end restaurants, true.

However top chefs will happily buy ugly fruit and veg if they taste good.

Supermarket fresh fruit and veg is always sold on how it looks, not on how it tastes. Shoppers don't buy ugly vegetables (except when shaped like genitalia).

I know by personal experience that sometimes my low population density area in the south gets a lower quality of vegetables than the state capitol. I was looking for something to cook. I won't say what only that the all the items at our local walmart were very small and bruised. This went on for two weeks. I drive to the state capitol and while I'm there go to walmart and they have what I need and they are the right size and of a higher quality.
Next day at our local walmart I look just to make sure and what they have there is just garbage. I have no doubt its the same for many situations.