If someone doesn’t want to do the work, let them not do the work.
If there are consequences inherent in their not doing the work, let them get a taste of those consequences for themselves.
That’s how people learn.
When you artificially remove the costs and benefits from people’s choices, you insulate them from the very kind of feedback that naturally inspires them to make important changes in their behavior.
If you’re constantly asking yourself how you can get people to do X, then it might be time to consider the possibility that X simply isn’t important to them. And if X really is important, you can help them see it simply by giving them space to learn in their own time.