Why not an Indian food chain?

My wife and I have lived in Kolkata, Bangalore, Delhi and Bombay. And we are pretty sure that recipes don’t cross borders too well. For example, sambar becomes sweet in Bombay. And South Indians add tej patta to almost everything. While these adaptations may make the dishes more palatable to local palate, there are surely many who want the authentic taste. After all, what’s the fun in eating out if it tastes like the food one has at home every day (Eating out from compulsion is another matter.)

Now, South Indian fried snacks are accepted across the country, as are Delhi chaats, and Bengali sweetmeats. Rajasthani savouries are also relished. So why aren’t there food chains for any of these?

I guess there are a few with shops across India, but none at the scale of, say, McDonald’s or KFC in USA.

Is it a only a matter of time for big chains come up in India?

Or is Indian food far more difficult to cook, and cannot be adapted to industrial cooking the way hamburgers are?

Or is it the ‘vision’ thing?