Gallup’s recent work indicates $100 billion is realistic, if not conservative. Gallup estimates 9% of U.S. QSR customers used on-demand delivery in 2016, producing a QSR delivery market of about $26 billion — despite many delivery services, such as GrubHub, Postmates and UberEATS, covering only a fraction of U.S. markets.
Source: Can McDonald’s Win in $100 Billion Food Delivery Market? | Gallup