Not everyone has to be a Jaeger pilot, or work for the PPDC.
Maybe Duke’s fulfilling another absolutely vital role somewhere else, remember, this is a global conflict.
Maybe he’s a Doctor Without Borders working in places where there’ve been civil wars because of people moving inland away from the oceans.
Maybe he’s a Marine Biologist desperately working to save the remaining ecosystems.
Maybe he’s a people smuggler working to get people off pacific islands.
And at the beginning of PR2 we get this heartrending scene with Stacker and Duke and Mako in the airport, and Mako and Stacker are going to Hong Kong, while Duke is going to Tibet or Malawi or Australia or Christmas Island or wherever. And they know they might never see each other again, and the world might end, and Duke is crying and trying not to and Stacker is struggling to hold back tears and they’re all hugging and saying goodbye.
And Duke turned to Stacker and says “I want to come with you, let me come with you.”
Stacker puts a hand on his shoulder and says “We need you out there. They need you. Go when you can do good, leave us little soldiers to our war.”
And there are SO MANY TEARS and Duke pulls Mako aside and whispers, “Look after him.” And Mako nods and
ALL THE TEARS GUYS