The tandoor is the largest single constraint in an Indian restaurant kitchen. It cannot be moved, cannot be turned down quickly, and requires a dedicated operator, and the kitchen is organized around those facts.
It runs hot continuously
A tandoor is a thick clay vessel that takes a long time to reach working temperature and a long time to cool. It is lit before service and stays hot throughout.
There is no equivalent of turning a burner down between orders, so the oven represents a fixed running cost from opening to close regardless of how many orders come through it.
That fixed cost is one reason menus carry a substantial tandoor section. The oven must generate enough volume to justify running it.
Ventilation and placement are not negotiable
The heat output and the fuel demand a heavy exhaust hood and a location that satisfies local fire and building requirements, which effectively fixes the oven's position.
Everything else in the kitchen is then laid out relative to it, including the marinating station and the bread preparation area, since both feed it directly.
This is why installing a tandoor is one of the larger decisions in opening an Indian restaurant, and why some smaller operations skip it and build a menu that does not need one.
Operating it is a specialist role
Reaching into a vertical oven to slap bread onto its inner wall and to lower and retrieve skewers is a distinct skill with a real risk of burns.
Restaurants therefore staff a dedicated tandoor cook whose entire station is that oven, which is a fixed labor position independent of how the rest of the kitchen is organized.
Timing is judged rather than measured
The oven has no thermostat and no timer, and temperature varies with fuel level, how recently the door was opened and how much cold food has just gone in.
Cooking is controlled by where in the oven an item is placed and by watching it, which is why the same dish varies more between restaurants than a griddle-cooked one does.
Why home versions fall short
Domestic ovens cannot approach the temperature or the radiant clay heat, so home tandoori cooking relies on broilers, grills and skillets that produce a related but different result.
Small electric and gas tandoors sold for home use narrow the gap somewhat, but the mass of clay that gives a commercial tandoor its stability is exactly what a compact unit cannot carry.