And when you do all of that, having the fountain machine on the customer side makes almost no sense.
The one I visit the most already removed the self-service fountain drink station and you need to ask them for refills.
One such time was at a Taco Bell, and I was trying to go inside because I saw that the drive-through line was massive. There was a hastily-drawn note on the door that said "go to drive-through for online pickup orders," which I thought would be pretty frustrating if you had ordered ahead! (Not that I blame any of the workers, of course.)
The solution I use is to order on the app and then they have to give you your food, either by bringing it out or by pushing it through the drive-thru window.
I think another reason for this is that it is also the easiest solution for handling the homelessness crisis. Requiring all orders go through the drive through by someone in a car is one way to avoid dealing with unhoused people looking for shelter/restrooms/water for a few hours and not spending money that they don't have.
There's one or two normal "registers" and like 3-5 touch screens.
The new process is: Order via kiosk/app --> Sit down and relax --> Food delivered to your table --> Now stand up again and get your own drink
The last step is kind of awkward and inefficient. So, it kind of makes sense for them to bring your drink with everything else.
The faster you can move customers out of the restaurant the more money you make during the busy hours, so efficiency matters.
Source: I worked with McDonalds 20 years ago as a vendor. They're pretty obsessed with efficiency. They even hire "actors" to simulate customers to test out new technologies, food items, and procedures in their test kitchens so that they can objectively measure the impact of various tweaks.