Bears, I may be not remembering things correctly - but aren't those two airports surrounded by I don't want any airplane noise over my neighborhood NIMBYs? Those things tend to go hand in hand with high income and expensive property values. Even the clowns living in Long Beach have limited their airport to 41 daily mainline flights (most of which are flown by B6). And LGB isn't even all that high-income.
I agree that suburban NYC should be a terrific market for making money with 738s to ORD, DFW and MIA. Maybe even the west coast if the runways are long enough. But look at ISP. Eagle doesn't even fly there anymore, does it? I used to fly there from BOS on the SAABs. Fun flight. Great little airport in a nice suburban Long Island location. By all rights, AA should be able to fly a few daily 738s from ISP to the hubs.
Maybe you're right and AA can make a go of it at HPN. AA still flies three daily flights from BUR to DFW.