The problem with this kind of thinking is that you're funelling large streams of money into pockets of criminals. You're also not solving anything, in practice people keep buying it - without actual minor controls (unlike ie. alcohol or tobacco) and with blurred perception (ie. same dude probably deals weed, cocaine, heroine, whatever). It is shifting market to black side with all negative consequences that come with it. It creates this disgusting alternative, unofficial layers in cities where law enforcement long ago gave up on enforcing this ban and ordinary people learn/know to stay the fuck out and ignore.

I can assure you the average teenager in a western country has absolutely zero issues getting their weed. In fact, the older you get, the harder it becomes (as your social circle tends to shrink once you have a job).

LOL. You should walk around some french cities a bit. Getting drugs for locals is certainly not a problem, despite harsh punishments like its 80s.

In theory yes, in practice no. It's smarter to legalise it, it cuts off income source for criminals, creates taxable income that can be actually used to fund help centers etc.