[timcederman]

Because their basic fee is just the delivery fee. They don't set the prices - the supermarkets do. The service fee is a consistent way for them to generate enough revenue to pay their shoppers and drivers, compared to the variability of user-provided tips before.

[edent]

That doesn't make much sense to me. There's no difference in labour cost for buying a single roll of toilet paper or a bottle of Champagne.

[LeifCarrotson]

Why isn't the delivery fee enough to pay for the delivery?