Within 15 years, fast food restaurants will be totally automated, from order taking and payment tender, to food processing and serving of the ordered product. Grocery stores will fully automate as well, but this is 25-30 years down the road.
Literally, you will order your groceries and consumables with an app, and either have them delivered to you, or you go to the “Store” to pick them up. there will be no more store faces or retail floors, which will save on building overhead. As the process will be almost totally automated, only a handful of employees will be needed to run it (if any are used at all).