I taught high school for 15 years and saw kids shrugging off the consequences of sleeplessness every day. In fact I taught AP psych so I got to talk to teenagers about their sleeping habits every semester. One unexpected result of the sleep survey I’d give them as discussion fodder is that typically a majority of my classes wished they had a bedtime. They know they still need guidance at their age.

Your argument seems circular to me. They shouldn’t have a bed time because they don’t need one because they didn’t have one. Sure— ideally you raise a kid that can set their own bedtime. But that’s not a guarantee even in supportive households (studies indicate peers have a much greater influence on teenagers than parents).

Sleep is too important for the developing mind to let a kid screw it up. To me this is the equivalent of letting a 13 year old do their own grocery shopping. If they can, “awesome.” If they can’t, the parent needs to step in. Hopefully they’ll able to self-regulate before they leave home. But if that fails then at least their brain had good sleep for the first 18 years of their life.