For a crash course:
The Kardeshev scale supposes that as civilizations grow, their energy consumption grows with them. But if there’s anything we’ve learned from innovations from the past, energy consumption goes down as technological progress continues. Think computers from the 60s versus what you’re using right now. But I hear you say, what about how consumption skyrockets as tech innovation proliferate among the common folk. Well, what’s to say that having different gizmos for different tasks is the epitome of innovation? Suppose they invent a retinal interface perfected to the point where you can simulate virtual environments by rewiring the computer in your skull cavity? Less makes more does it not? Who’s to say that a true type I or II civilization isn’t in permanent hibernation mode in their own virtual universe, all the energy they need is received from a neighboring star.