Back in the 2000s on the Sepia Mutiny blog I would get frustrated with commenters who would talk about India as if it was analogous to Cuba or Israel, in that a group of American nationals with family ties could influence the shape of American policy. This was always a crazy proposition.
The reason that focused American ethnic lobbies could shape Cuba and Israel policy is that these are small nations which to be frank don’t matter that much.
There’s no Germany lobby. There’s no Russia lobby. There’s no China lobby. These nations are too important to get caught up in pure interest group politics. Similarly, there will never be an “India lobby.” Even personal relationships and affinities between leaders are irrelevant when realpolitik is too important. Think of the fact that Trump clearly has an affinity for Putin, but the American government continues to impose various sanctions on Russia.
Note: Because of its embeddedness in the Great Power jockeying between the USA, China, and India, there will also never be a “Pakistan lobby.”