> Age to purchase tobacco and pornography (yes yes, I suspect most people get their porn for free online regardless of age now).
You didn't include alcohol which is already at the age of 21 in USA, but not everywhere else in the world (in my country, it is 18). Yet driving, is age 16 in USA, 18 here as well. My point is that the world is bigger than just a few countries, with different age limits. We should attempt to study the pros and cons of each before drawing to conclusions.
Also, the fact something (e.g. alcohol) is illegal to purchase doesn't mean it cannot be obtained. With driving a car that is going to be more difficult because the car is licensed to a person, and learning driving via obtaining driver's license is important.
On the longer term, driving a car becomes irrelevant though, but I suspect the same is true for tobacco.
You also didn't mention that other hot subject, firearms.
> This wouldn't make any real difference to politics because young people don't vote.
Really? Do you have data to back this up?
I know that, from personal experience, I voted as soon as I became 18.
> open a bank account
I think I was able to open a bank account at age 12. Not that there was a whole lot on it. That's OK, it allows youth to learn how financials work and managing money. What is not OK is allowing youth to get in debt.
The only loans a student (read: 18+) is able to get is via the government, for studies, and they gotta be paid back. I don't see a problem with that system, in the sense that is must be abolished.
I think it is great to have young people work. It teaches them what they want, and not want to do. It stimulates them to start a study, put their heart and soul in it, and finish it. Because who wants to pluck berries for the rest of their life? Only those who never done it before.
> * You could not be tried as an adult in criminal court until age 25. The number of adult violent offenders in prison might decrease as much as 70%.
How are you going to hold those of age below 25 accountable? The justice system exists to find balance between 'damage received', and 'damage done'. If those who cause damage are not going to be held accountable in any way then that does not seem justifiable to me.
However I would agree that a young person should receive, generally, less penalty than an older one. We got a reasonable system for that already: we punishing recidivists more heavy.
My opinion on the whole matter: the term young adult exists for a reason. Part of puberty and being a teen is getting lose from the stigma and lack of responsibilities associated with being a child. We need to let our children taste how it is to be an adult and all of the above are part of exposure. If we treat young adult as if they're children, they are going to remain children and will get a revelation when they reach adult age (in your PoV that should be 25).