The early days of drive in was waiting in your car in the parking lot and wait for a server to come out to you to take your order. Then they return to your car with the food for you to eat in your car in the parking lot. They often had trays that hooked onto your window or trays that would sit in your lap to eat from. This food was diner style food and wasn't quick to make like fast food today is.

These styles of restaurants fell out of style when cheap and quick fast food came along. This combined with Americans are usually only interested in the latest things or styles, many of these old style restaurants went under and disappeared into history. The Founder movie covers some of this when the McDonald's brothers came along.

The ones that didn't die like A&W adopted the eat inside model with a drive thru window for pickup abandoning the older model where their waitresses would roller skate out to your car to take your order and deliver food.

Then there are newer chains like Sonic in the US that have this old style pull up parking and a drive thru with outside seating. This is more of a nostalgia play for consumers and it worked as it was a trip to something that wasn't around anymore so it was new again.

I assume this Chick Fil place is doing something similar in this photo or they are just delivering food during the pandemic to people that preordered ahead of time in the rain.