As for actual fast food, while the process is optimized to the extent possible, that optimization usually involves the restaurants having their own supply chain of specific ingredients. Grubhub would have to gain access to the same ingredients to successfully impersonate chain restaurants.

What I can see them doing is just launching 100 different fast food brands selling the same food cooked in the same dark megakitchen, because why not, DDoSing consumer choice with fake brands is par for the course these days.

Some pizza is not fast food.

Market participants all care for different reasons.

As far as assuming the business identities of "non participating" restaurants, that sort of thing has a long history - it is a favorite of various organized crime rings.

So in that sense, it does seem a natural fit for GH.

[1] https://www.businessinsider.com/diners-discover-that-pasqual...