Libertarianism sounds great when you're a teenager because you don't think about boring shit like clean water, credit card consumer laws, corporate veil laws. All you think about is how you're going to become rich and famous and never have to worry about that shit anyways.
The sad realization that dawns on you towards your late 20s is that you ended up just another middle class working stiff never enters your teenage brain. You just expect to make millions by the time you're 30 and you'll be damned if you have to share it with anyone or if anyone will get in your way.
Vast majority of us grow out of it, but some remain mental teenagers forever.