Well there are actually quite a number of options in Queens for people with 1.5 million to spend. Sunnyside Gardens is a lovely and historic complex close to the City, which I think is generally under a million for a house (albeit smaller than the one on 86 St). Kew Gardens is further out, but it is connected to the train, is a beautiful neighborhood and has gorgeous houses selling in the 1 to 1.5 million range. Forest Hills Gardens, mentioned above, is connected to the train, very well established and very charming -- its more expensive but you could still find something quite nice for $1.5 million I'm sure.
Then, someone with $1.5 million to spend (and interested in a house with a yard like the place on 86th Street) could well look to inner suburbs in Westchester, like Bronxville or Pelham -- which have a very quick commute, are very well established and are affordable to people with $1.5 million in their pocket.
For me, Jackson Heights beats them all. But, realistically, given that there are a relatively small group of people with that kind of money to spend and a relatively large number of options available to the people willing to spend it, I'm not sure that JH is likely to catapult into the higher end category. But then again I could be wrong, who knows?