Because the drive thru has a sensor that marks when a car pulls up to order and how long it takes the car to exit the drive thru which makes for lots of nice objective numbers on wait times for a store to get slammed on if they don’t prioritize the drive thru.
The one thing people have not mentioned so far, however: many businesses do not have toll-free numbers. I think the reason people often give the phone priority is because the callers might be paying by the minute for the call, even when on hold. Not everyone has an unlimited calling plan.
I would truly doubt that any business gives the phone call priority over a customer in line because they think the person on the phone might be paying, per minute, for the local phone call.
To be clear, I think phone calls get priority, just not for that reason. Many times I’ve said to another employee ‘hurry up, that person’s been on hold for a while’, but never added on ‘and they’re racking up charges on their phone bill’.
