The market can't discover this when consumers are misled by the delivery services. 10% is reasonable. Let the delivery service add a fee to recover their cost rather than take the food provider's profit. Otherwise, these food providers are going to go out of business (and be bought by the delivery services).
The market determines what is reasonable, not you (or any one person). "Recover their cost"? What is this, communist Russia?
So what if the food providers sell off to the delivery services? Perhaps it will result in a better match for the market demands. Preserving jobs isn't the goal of capitalism, profit is. Those businesses who try to go too far toward extreme profit usually fail when smaller, more nimble upstarts dig the foundations out from under the bigger ones.