It’s in the name. It’s fast. You order at a drive-thru and you’re on your way in a couple of minutes. I agree though that prices are insane now and doesn’t justify the quality. I’d rather go to an asian restaurant for their lunch specials and get more for my buck.
In a lot of cases it's not actually fast (not just waiting in line at the drive thru, but also the time driving to and from the place), but people would apparently rather sit in traffic than cook, for some reason.
Cooking takes time, ingredients, and if you want it palatable, ability. Fast food takes driving up to a location and saying "give me something easy".
It's not as fast as it used to be, but it's still relatively quick, especially if it's on your way home from wherever you are. Any extra time is just spent doomscrolling on your phone or listening to your preferred media pundit.
See, I don't get the fast drive through thing. I pull up to the drive through. They have two lanes. Both are full and there are 10 cars ahead of me. I have to wait 10 minutes or more just to place an order and 10 minutes to get to the window to pay. It's generally not fast at all.
Another thing I haven't seen mentioned is its one of the last places open late anymore. I live close to a city, but if I need to grab something late (9:30+) fast food is about the only place open.