That sounds a little different. They were offering three options and four out of six sides. I'm talking about 1-2 fixed options on any given night, and someone literally cooking in the back of a van while it drives a circuit. Discounts for pre-orders, or for people coordinating their block/building to order en masse, etc.

One driver, one cook. Driver optionally runs deliveries to the doorstep if need be.

Like an ice cream truck for hot food?

Basically. Imagine an ice cream truck, but with some rice cookers and curries going in the back, playing Bollywood music, and driving a route in the suburbs. Plus an app estimating time until arrival, taking orders, etc.

There was an Indian restaurant near my office that was almost always empty - good people and decent food, but they never did anything to try and stand out. They've disappeared now. Were I in their shoes, I would've been trying something like this on the side for sure.

Don't most major cities in the US (and the world) have dozens of these?

Food trucks are generally quite static and not in the suburbs. They pick a spot and stay there for hours at a time. At least, the ones I've seen around the world.