Hang on, are we not concatenating inbound tourism per se with visiting family in an ethnic minority community? Hence what works well in one part of India does not scale up in remotely the same manner to anywhere else? Or am I missing something really obvious. Again.
No you're not. It's likely that people with family links in Birmingham have links with north India: the flight is to/from Delhi and Amritsar. That being the case, it is unlikely that a flight to/from, say, Bombay or Bangalore would work.
The geographical size of India should not be underestimated.