But your argument has one flaw, it's not on the Island, that natural border I strongly believe greatly defines the unique brand that Manhattan offers.
Once you are over the water, it just gets cheaper and cheaper the further you go out.
My conclusion, Astoria a lovely place but not Manhattan!
So rent per square ft will be only Max 75% of the cheapest apartment under 105th St.
As Astoria is in such a conveniently close proximity to the city, I think values will continue to rise at the speed of the city properties.