Originally Posted by skywardhunter

I suppose it also has to do with lack of exit immigration in the US, hence no sterile area for departures. Most small international airports simply have a passage-way from arrival to the sterile departures area, not a major infrastructure need, but since there is no sterile departures area in the US this affects it. Surely for a few major airports, especially JFK and MIA with the connecting traffic to South America, it would make sense, but then there's the additional issue that terminals and gates in the US belong to airlines so each airline would have to have their own arrangement for this, as opposed to a common terminal