If McDonalds had people on site to deliver it would be cheaper. But it still has to be pricey enough that they can afford to pay the delivery guy, per hour, enough to make it worthwhile.
Edit; checked here; 1 Big Mac large menu is 11.63 euros including delivery. 7.65 euros for takeaway of the same menu. Distance similar to yours.
2. How much do you think it should cost, exactly? Do you mean to imply that the cost structure of such services should be much lower?
The volume won't be there to make up for it because all non-free delivery is too expensive for a good many people. Quite likely there is a price point at/below which delivery will start to appeal to larger segment; perhaps at that price, almost everyone will opt for delivery instead of going there. That price is likely below the costs of providing delivery.
It's probably better to just focus on and capture the market segment that forks up for delivery (because it's worth it to them) rather than chasing an elusive volume increase at lower margins.
If they could knock a dollar off delivery but triple the volume by doing that, they probably would; and likely they've already done that sort of price optimization.
Another thing to consider is order size. If you had a big group of people and had 10 of these meals delivered, maybe the economics would be better?
How much did it literally cost to have it delivered? (Assuming it was not $20 on the dot)
How much extra beyond what you would have paid in person do you belief it should cost and why?
Even in those circumstances, the fully loaded cost of the driver to the customer in some no-name suburbs was around $18/hr, split between on average no more than 3 customers. So on a $5 pizza you'd pay $11.50 for the pizza, tax, and delivery costs.
Contrast that model a bit with delivery apps:
(1) Doubles are rare, so the driver earns less per hour.
(2) There's still a back-and-forth between housing and food, but extra latency was tossed in since you have to wait after your delivery to figure out which place you're going to be grabbing food from. I.e., drivers make less per hour.
(3) Enough restaurants aren't fully optimized for fast deliveries that the drivers easily tack on an extra 5 minutes waiting for their food, resulting again in fewer deliveries per hour and less money.
(4) We can keep going on about why drivers are getting fewer deliveries per hour, but the consequence is that drivers need more compensation per order to be willing to do that over another job. Easily 50% more. Your $6 delivery cost is now $9.
(5) Combine that with the fact that they know the tip ahead of time. There are basically no consequences for skipping an order you don't want to take, so the only people getting hot food are on the high end of the tip scale, which is already higher than the pizza place average. Conservatively, bump this up to $12 per delivery, but when I tried DoorDash I was making $36+/hr for at most 2.2 deliveries per hour. You do the math.
(6) On top of all that, there's a middleman in the transaction with their own fixed costs they need to cover. The pizza place is happy just to sell more pizzas per hour by having a delivery option and charges a fee large enough to roughly offset the cost to them of providing drivers (included in that initial $6 estimate I provided). Uber Eats can't increase their profits _just_ by increasing orders per hour since they didn't have a cut of any of the initial transaction. They have to charge their own fees on top of everything else you're already paying.
I'm actually a little surprised the total bill was only $20. Was it cold?