Shouldn't need to pay five times the price, if you're making four times the quantity. Those four Hawaii airports were pretty quick to produce, and could've been sold as individual airports
It's enough checking the relevant backdoors, to verify how wrong is this:
Hawaii1 was announced in January 2010, and released in October, 9 months.
work on Hawaii2 started shortly after that, and was released in July 2011, another 9 months.
KLAX was announced in October 2010, and will probably be released in August 2011, roughly 9 months, and this is taking so much, because we tested an entirely new development method, JFK was made in less than 6 months, KDFW took about 7 months. PHNL took 7 months also, from the same developer of Hawaii1/2
There's a lot of overhead that doesn't depend on the airport size, which is collecting pictures and any other data, setting up a project, writing documentation, installers, etc and, on top of that, people expect more attention to detail to small airports, so they end up being as long to develop that large ones, but they sell roughly a quarter.
So no, the economics of small airports are not favorable, and this proven by facts.