You could not have picked a better example. Maybe one equal to, but not better. I just recently watched something on a Kennedy airport incident. The incident isn't important, the traffic is insane. It made me come to the conclusion that the northeast has too many planes and too few runways. Although your suggestion makes perfect sense, I think all of the ATCs are union. That's a separate issue. As a union member all of my life, I can tell you that many people prefer higher workloads just to be closer to home. I look at it differently. I'll drive further to make my 8 hours at work easier. But I'm in the minority.
Kennedy tries to get over 30 planes an hour landed. That's minimum. During busy times they can have close to two dozen planes in holding patterns near the airport. Some holding patters have to overlap others, but they are at different altitudes. Then the ones flying in from Europe get priority due to fuel concerns. When I got a visual of what it looked like above and near Kennedy airport, I was shocked. Passengers land. But they never knew they were flying in circles for the past hour or so.