one might ask why the commission is necessary at all. unless you're placing an enormous order, a large order isn't really more expensive to deliver than a small order. the bottleneck is much more likely to be the number of stops you can fit into a single loop before the food gets cold than the volume of food you can fit into a single vehicle.

the only answer I can think of is that they don't want the customer to realize the true cost of delivery.

I don’t know about Uber Eats, DoorDash, or GrubHub but SkipTheDishes here in Canada doesn’t use “loops”. Every delivery is one-to-one. You place an order, the restaurant confirms it, a nearby driver accepts it and travels to the restaurant to wait for it to be prepared, the restaurant prepares the food and gives it to the driver, the driver delivers it.

It’s very inefficient unless your goal is to optimize for quickest delivery and hottest food, which is what it is. However, there is one major efficiency it has over the restaurants paying for their own delivery drivers is that SkipTheDishes has a large pool of drivers to dispatch orders to from all of the restaurants. It’s like having a thread pool you can dispatch jobs to rather than having dedicated threads allocated to each work queue (which may end up idle a lot of the time).

Another thing you have to consider is that the drivers need to earn a living. If they only get one or two orders a night and spend the rest of their time waiting around then they can’t afford to do the job so they’ll probably quit. These delivery services ensure that drivers will have a busy shift because their scheduling systems don’t overbook drivers. That all goes out the window if you ask every restaurant to hire their own drivers.

'Batched' orders are very common in the US. With some very popular restaurants on Grubhub, they'll batch 5-10 orders for a single apartment building, have the courier bicycle to the building and go door-to-door delivering them, sometimes multiple on the same floor.

A larger order is more expensive if delivering by bike (think urban areas). The bike would have limited storage space. One large order means fewer small orders performed in parallel by the courier.

that's a good point that I didn't think of. I live in a less dense city, so deliveries are usually by car here.

15% is around how much restaurants budget for front of house staff, so it would be acceptable at typical prices.