That doesn't make any sense. It's a choice for restaurants to sign up and they have like 10 services to choose from. If it's not good for the restaurants they'll just stop using it. Any marginal delivery is pure profit for a restaurant.
There have been many cases of delivery app companies doing things like taking out ads in the company name with a phone number and website that looks like the restaurant but is actually the app company. So they feed off people organically searching and getting deliberately redirected.
> If it's not good for the restaurants they'll just stop using it.
it's not that it's not good, but that they noticed the delivery funnel is growing (and foot-traffic funnel correspondingly shrinking). This means if they don't participate, they risk losing this revenue stream to their competitors (who do participate).
This is what happens when your business becomes a commodity to another business. You have to make sure your business has a value proposition that prevents it from becoming a commodity (or make sure you are very efficient at production and scale up to take advantage of your product becoming a commodity).
Edit: i suspect things like massive, efficient industrial kitchens producing delivered food may become the new norm.
