I am glad someone is doing the math. It's too bad it isn't the drivers. I assume this applies to UberEats' competeitors like GrubHub, Postmates, and DoorDash.
The problem here is that the average profit margin for a restaurant is under 30%. Fast food such as McDonalds reported profit margins about 22% in 2017. Casual dining or family style restaurants have a profit margin between 5% to 10%. Lastly, full-service restaurants such as fine-dining have average profit margins of about 6.1%. (source)
Based on the average profit margins above, every restaurant that engages Uber Eats will lose money on every order they take. The more orders coming from Uber Eats, the more money a restaurant would lose.
On the other side of the phone, you will have to pay a “booking fee” for your delivery that is also being paid directly to Uber. Thus, Uber is getting its cake and eating it too.