truly great indian cuisine is found in home kitchens, and never in restaurants.
eating out at restaurants in the sub-continent is an event, a rare thing; you are far, far more likely to eat at each others homes.
because eating out is an event, the grandest cuisine around got shoved to the top - the cuisine of the moghuls. and as a natural piggy back, some punjabi food. south indian food and gujarathi food made it because of their popularity as providing ideal light lunch fare. so in india, about thirty years ago, all you had were (indo-)chinese, punjabi/moghlai, gujarathi and south indian restaurants. and natch, these were the same ones you found abroad anywhere.
if you wanted regional - for example, sindhi, maharastrian, konkani, keralaite, goan, mangalorean, andhraite, kashmiri, rajasthani, parsi - your best bet was to be invited to someone's house. if a restaurant wanted to be daring, they'd offer hyderabadi or lucknowi food - similar enough to and as grand as punjabi/moghlai that they weren't taking a serious risk. thats my experience with classical hyderabadi food - a couple of shmancy places (very good they were too, till the cooks got poached).
things are changing now - there are a couple of decent mangalorean restaurants in mumbai and one of the five-stars is enjoying a bit hit with konkani, for example. the big mind change that has to occur is that urbanites in india must be willing to go and eat home style cooking in restuarants. once that takes place, we'll see an explosion of all the fabulous regional varieties (konkan is as different from punjabi as korean is from italian). jhumpa lahiri and arunadathi roy will write winsome, yet tough articles about our heritage, the role of women in the kitchen etc. it'll be picked up by the b.b.c. and be made in to a ten part special. some clever entrepreneurs here in london will then open some regional restaurants. and then, only then, i'll stop howling.