"post-flight" lounge access
 

i am sure people have thought about this before but if there's pre-flight lounge access, is it reasonable that a post-flight lounge access is also doable?

except that most lounges are only accessible thru the departure hall.

sometimes my flight arrives early or there's a few hours before i will be picked up at the airport after my arrival, i can certainly use the lounge - especially at some crappy airports.

Some airlines offer arrivals lounges at certain airports. CX offers use of the AA arrivals lounge at LHR, for example. BA and VS also have arrivals lounges at LHR.

In general, though, your comment about departure side versus arrival side is probably the very biggest reason you only see this in a few airports. That is a huge cost, setting up a lounge, and to have to put one on the arrival side? If you are arriving, I guess the airline will also argue that you soon will be in a hotel (although it sure is nice to shower and clean up at LHR upon arrival.