A question from [travel.stackexchange.com about luggage carts](https://travel.stackexchange.com/questions/121393/why-do-luggage-carts-cost-money-to-use-in-u-s-airports-but-provided-free-of-ch/121413?noredirect=1) prompted a discussion on the economics of airports. The gist was:

American airports have much lower passenger service fees which 
 are capped at USD4.50 per FAA rules than foreign airports, which can easily be USD20-50 per person. This results in much
 lower number of amenities at American airports compared to other international airports. 

You’d think they’d try to make it back with landing fees. But Tokyo Narita airport’s landing fee is JPY1550-2000 yen per tonne. A 787-8 has a weight of 172 t so the fee would be ¥258,000 - ¥344,000 or so or roughly USD2300 - USD3100. San Francisco SFO’s landing fee is USD5.54 per thousand pounds. A 787-8 landing weight is 379,200 pounds so the landing fee is around USD2100. There doesn’t appear to be a significant delta here to account for the difference in passenger fees. 

My question is: **Why don't airports simply increase the landing fees to compensate for the lower per-passenger fees?**