Your memory does not deceive you. NYC is indeed significantly smaller than its OTL counterpart in 1896 for the reasons you mention - it's just that, despite this, it's still the largest American city because it had such a head start (having almost twice the population of its nearest rival when the ENA was originally formed). There are less reasons for people to move to NYC than OTL, but there also aren't any particular reasons for people to move to any other east coast city in preference to New York.I seem to recall, way back when the narrative was around the late 18th, turn of the 19th century and the Jacobin wars were raging, that you did not believe NY would dominate, because major immigration as well as trade into the Mississippi Valley would flow up the Saint Lawrence to Mount Royal, which would become the Big....Maple I guess. That NYC of OTL was a fluke of chance, nothing deterministic about the Hudson Valley to the Great Lakes being some sort of predetermined optimal regional channel. Rather it only looked that way OTL due to Yankees not having the Saint Lawrence in their borders, so Montreal (OTL spelling) was deprived of its natural flow with most immigration being diverted south of the US/British possessions border, so the second-best channel westward was favored.
At the same time, I seem to recall someone or other arguing that meanwhile Fredericksburg would also divert, or preempt, which ever term is better, more of OTL's concentration on NY to itself, and we'd wind up with New York being a decidedly second or third rate city, taking a back seat to Mount Royal, Fredericksburg, probably behind both Philadelphia and Boston, maybe even Baltimore or Charleston.
It has been many years since this discussion and maybe my mind is playing tricks? But whatever happened to all that then? How come NYC is still the Apple here?
This is partly because city limits are defined a bit differently in the ENA (due to how the burgess seats in Parliament work) than the more fluxional way they are and were in the OTL USA.