It's a standard I grew up with - if anything I wonder if I should be raising it for inflation.

Much like servers, delivery drivers aren't paid properly if they aren't tipped. But, in my mind, the quantity of food matters a lot less to the delivery driver's work, unless it's a large enough order to require multiple trips from the vehicle.

For the amount of time a driver has to work to drive to me and park and bring my order to the front door, yeah I think $5 is more than reasonable. They probably spend more time on me than a server in a restaurant does, in a lot of cases.