Delivery would be an obvious one. I could be wrong, but except for pizza, I don't believe any of the major American fast food chains deliver.
Maybe they've all done the math and it doesn't make financial sense, I don't know. But there's certainly nothing inherent about the type of food that makes it impossible; I've had great burgers and fries delivered by a few independent restaurants.
Funny you should mention that on this story...
Just so you know, it's a 3rd party doing that delivery.
In Malaysia and Thailand some BK and McDonald's deliver. But then again, I don't know if it's up to them to decide or if it's being done because of the competitive environment. You can basically find great food at almost any given time within walking distance.
There's the competitive aspect in economies where street-food is the norm but then keep in mind that it's dirt cheap to deliver there. In Thailand a delivery worker earns 220 USD a month.
seems like new food inventions drive alot of the marketing behind their competetors
trying out new menu items is just 1 thing that pops to mind, and I'm probably completely missing 100 other things that a burger place could inovate on