You just said the teens will do it because they think they'd be cool to their friends. Who do you think they listen the most while they are still teens, their parents or their friends or the school?
Because in some cases teens who do all of those vices change after they get older, some friends get married and work at their father's business, some become successful working in the city. They mature eventually and stop the nonsense. Those who got deeper got worse though. I must depend and who they listen.
Kids listen to their so called
cool friends, they don't listen to their parents. In fact, kids hate to listen to their parents and many of them intentionally do opposite of what would please their parents. 14 years old kids smoke cigarettes man, they drink and take different drugs, they gamble, they do everything bad because for some strange reasons, it means that you are
cool and kids want to be cool, they want to gain attention and respect from their inner circle.
It's called peer pressures, some are bullies, or if you wanted to join the group, then you have to also do what they did so gambling could be part of that group. And not only gambling though, it could also be one of the so called coolest things, which is to smoke.
As they grow, they mature but the problem is that many of them are sometimes left with anxiety, depression, addiction and so on. Today you are a cool guy if you are on Prozac. The world has gone crazy. The maturity situation is getting worse in kids who turned adults recently.
World is evolving and there are societies right now that the influence of parents is very small unlike before wherein before you can even drink alcohol, or go to a party, you need your parents consent first.