It's a well-known fact that online ordering is the way of the future. Restaurants actually take a huge hit for having another company add their menu online and can take profits up to 20%.
During the COVID restaurants really had no other choice because the general public would be home isolated. Customers that loved their restaurant life were taken from and one simple way to enjoy their favorite foods was to order online.
The thing to remember is that restaurant owners are usually traditionalists and they are willing to change their process even though you show them that you are saving them a tremendous amount of money.
So the best way to figure out the best way to address this issue is by asking questions. Talk about their process and how they get orders that come in and how the kitchen sees these orders and starts the prep work to meet the online order fulfillment.
Ask them how they communicate with prior customers that ordered a year ago. Do you know who these customers are? Is there a way that you can figure out why they stopped ordering from your restaurant? If there was a way that you can see this data and reaching out to your customers and offer them a special or gift can you do that with your current system?
When asking the restaurant owner these questions you are leaving them with self-doubting concern that is real. You are opening them with the idea of how to better manage their past customer and current customers. When this is understood start talking numbers.
What does the average online order cost? What is your profit after everyone is paid? What number would you think that customers that once ordered from your restaurant online aren't ordering anymore? If they do not know make up a number and stick with it. For this example, this number is 75 customers. Bring back the average order cost and let us do the math. Take 75 and times that by profit and multiply that cost by day/week/month/year. Show them the cost earned in revenue.