It's really not clear it did. The market, as such, changed overnight: tables in restaurants are worthless (for some period) and internet delivery is presumably

It's really not clear it did. The market, as such, changed overnight: tables in restaurants are worthless (for some period) and internet delivery is presumably a roaring trade. Restaurants have unexpected imbalances in their revenue streams; presumably if this was expected to go on a long time, they'd be renegotiating their contracts with GrubHub et al on the new basis. This is an emergency order, for the period until restaurants can re-open for dining in. The mayor has apparently decided that local, small businesses need to be saved from the terms of their contracts with the third-party aggregators due to the suddenness of the change. I'm a little surprised that the mayor has the authority to tear up those contracts, in any case.