I think TEP hints at what was going on. There was up 'till the 1920's a pretty well defined eastern seaboard establishment. They organized the first tier clubs at the best sites in Philly/NYC/LI/and Boston. And they used a pretty finite group of acceptable architects. (Note how many MacD Raynor courses there are on LI. There's one behind every gas stateion, as far as I can tell. That was the old, big NYC money all working off the same list.)
Is there an old line eastern seaboard club that Ross worked for? (Do GM/AronimInck count?) I suspect Ross was viewed as a little too proletarian for the Knickerbocker Club/NYAC set in the East.
I raised a similar point in a different post, on Jeffersonville GC. I often wondered why Ross was not represented on Long Island-- being as deep as it is in courses designed by "Golden Age" architects. This is a plausible reason, that the other established architects (CBM/Raynor, Tillie, and Philadelphians) kept Ross out of the area. I believe TEPaul raised this point in response to my question originally. Also, think about these few things; CBM traveled in the same circles as many of the "Gold Coast" contingent of the day, and perhaps he had more to do with it than any other; also, consider that Ross was a native Scotsman, and CBM was an American (yes, he had Scottish lineage, but was NOT a native Scotsman; he studied there, but was American. Perhaps there was some "jealously" going on in terms of being thought of as "authentic"?). Perhaps CBM was slightly jealous of Ross being a native Scotsman, and, because he had infiltrated the Gold Coast society of the day on LI, he persuaded them to use other designers (himself, SR, Tillie, etc). Think about it. No Ross on LI, I don't think any in Westchester, and the same for the Greenwich area of CT.
The same could be said for the Philadelphians, although there are a bunch of Ross courses around Philly. Perhaps they weren't as successful in keeping Ross "off their turf".
In terms of golf courses, the closest Ross came to New York City and LI were Knickerbocker (Bergen Cty, NJ), Plainfield (these might qualify as "old line Eastern Seaboard"), Echo Lake (Westfield, NJ), and several others in "bedroom" communities for NYC. Nothing in the Connecticut suburbs (Greenwich, etc).
Most Ross courses in New York are located well upstate, particularly around the cities Buffalo, Elmira, Rochester.
In Boston/Mass., don't forget, Ross was strong there; this could have been helped by his ties to the Tufts family. Same with his connection to clubs in the southeastern US.
As an aside, Dev Emmet was also a member of the "aristocracy" of the day. He is obviously VERY well represented in this region of the country, particularly LI.
(Travis, I often wonder about. He has a few "old money" clubs with his name on it (Round Hill, Westchester, GCGC, GCCC, North Jersey, White Beeches) but he was an Australian. Perhaps his connections arose from GCGC).