>>25617231
Lets face it, most people can suspend their disbelief for older people playing teens in TV and movies, and when it comes to certain story lines American audiences actually prefer the actors be over age.
It's all about managing risk.
You can take more risk on a teen actor who is most likely shit at acting, has "special" requirements and labor considerations related to production, and is a walking talking HR landmine.
Or you can just throw some makeup on a actor in their 20s who is a known quantity that you know will do a sold job without any unexpected risk.
From a risk management perspective the choice is obvious, and usually it's for the better quality wise as well.
You not being able to jerk it to actual underage jail bate is a small loss, but a loss studios will gladly make.