They can. It takes a tiny effort and then it becomes habit.People from New Orleans and surroundings cannot say "ask." It comes out "aks" (or "ax"). I noticed that when I moved to SE Louisiana from north Louisiana over 50 years ago.
I agree that pups is annoying, but I do use it, though never orally, just when writing. And the the only time I write about pickups in really any context is on this forum. So, my thorough laziness and embarrassing indoctrination is at least somewhat contained.pups