I've given this explanation before on HN - absolute numbers are relatively high, but the ethnic diversity of the Asian community in NYC is low.
Several smaller ethnic groups are not well represented in NYC.
Indian isn't a singular identity but dozens, same with Chinese, Pinoy, etc.
If there's a specific Asian subethnic cuisine or community you want to find, you will always find 3-4 options within commuting distance in the Bay Area, but never really in NYC.
For example, if I want authentic Uyghur samosas, I have 3 options in SF, but only 1 that recently opened in ALL of the NYC metro.
Same thing if I want Bihari style cuisine, or Pakhtun cuisine, or Central Vietnamese cuisine .... (you get the point)
This doesn't matter if you are a large ethnic group like Cantonese or Gujarati, of which there are tens of thousands here, but it does matter if you're a smaller subgroup or you wish to experience different subgroups.
On top of that, Asians are well represented outside the Bay Area in other areas in the West - I can go to small town California and not get treated as an "other" because they had a community of ranchers who moved from India 100 years ago or have a multigenerational Filipino community.
If you go to small towns in the East Coast, you absolutely do feel and get treated like the "other".
I don't need to worry about a racial abuse in a town like Visalia but I have been called slurs in similarly sized towns in Upstate New York.
At the end of the day, California is Minority-Majority, and the rest of the West is trending the same way. Perpetually being a minority like out East, Midwest, or South sucks.
If I or my family ever needs some form of support from the government or social services, I can safely assume that resources exist to meet our cultural needs, but the same cannot be said out east.
Furthermore, we are VERY well represented in all rungs of government and civil service out West, but it's not the same anywhere East.
It's like what Ali Wong said - SF is basically Asian Wakanda