Why Hasn't the Drive-thru Model Expanded?

It's been exactly a year now that we call São Paulo home. A big shift from our days in Connecticut.  There are many wonderful things about South America's largest city, the magnificent restaurants, a vibrant cultural scene, the warmth of the people, to mention a few.  One of the downsides of life in São Paulo - with a population of over 11 million people - is traffic. It doesn't help that over 600 vehicles are licensed on a daily basis.

Which leads me to the following question, why hasn't the drive-thru model expanded beyond fast-food chains and a few ATM machines?

When we lived in Florida, I remember driving through Farm Stores Express to pick up last-minute groceries: soda, maybe a carton of milk, a box of cereal or a pint of ice-cream. It was fast, convenient and a relief not having to get out of the car specially when the temperature was close to 100F, which was rather common.

Brazilians are addicted to 'padarias' the wonderful intersection between a bakery and a c-store, loaded with Portuguese tradition.  Couldn't a drive-thru padaria succeed in the many busy corridors that lead to and from residential areas in a massive urban sprawl like São Paulo?