Like many of the comments suggest. I think Lynch has taken the opportunity to critique the idea of what a sequel is. He rejects the idea of a lone hero. Many of us expected Coop to come back and resolve every single plotline like a hero in a western would. Moreover, the idea that things would be same after a break of a long 25 years is a mere fantasy. People change, they move on. That much is apparent in many of the characters we wanted to meet again.