Same as they always have. It's fast. You can grab taco bell in a flash compared to even the best run diner or cafe. And you don't have to sit around with a bunch of strangers that are essentially walking disease vectors to do it, unless you want to.

The draw of fast food joints has never been primarily about the food quality, or service. Yeah, you'll likely pick the place that has what you consider better food, and avoid shit service, but that's a different thing.

Even joints that pretend to not be fast food (like chikfila) only pull a small portion of their consumers on the food primarily. They might draw some customers away from other fast food places, but not from sit-down places like you're talking about