Pathetic and disgraceful. Canada was the same as well.

Arrived at Dubai airport a few weeks ago.

Within 15 minutes we were through immigration, and our rifles were waiting for us at customs.

5 minutes later we ready to leave the airport, but had to wait for Walter to answer the call of nature!

That was all the delay we had!

I wonder if JFK isn’t always like that. I came back from Zim a few years ago and a similar thing happened. Several red-eye flights came in from Europe and Africa all at once and that huge waiting area (about the size of a Target store) was overflowing within minutes.
On the other hand, when I arrived at Dulles early AM a few weeks ago, no lines at all.

Why should airport managers plan, when they don't loose any money by not planning?

The inconvenience of the traveler is most unfortunate, but until it affects profits, no one in a position of power is going to worry about some future problem.

One reason for the big delays I am sure is that they did away with the kiosks, at least at LAX. So, all US residents have to see a CBP agent instead of being cleared by the kiosk and heading out.