That's probably asking too much from some folks.
There are a couple things that are just terribly wrong about your assertions here. For starters, your insistence that the government will be selling marijuana to children (i.e. persons below the age of 18), when marijuana use would be regulated like any other legal drug, such as tobacco being sold only to adults above the age of 18 and, at least in the US, alcohol to those above the age of 21 (it's 18 in the UK and many other countries). Gee! There goes that idea! Do kids under the age of 18 still smoke cigarettes and drink beer? Sure. If they can get their hands on them. The funny thing is kids have much easier access to marijuana when it is sold by a drug dealer they can know through a friend, instead of a store clerk who would have to card them and ask for ID. In essence, your argument here is self-defeating, because you are basically arguing for the idea that makes it MORE PROBABLE FOR KIDS TO ACCESS MARIJUANA.
Secondly, the government? Really? That's funny. The government and ole Uncle Sam is certainly going to want a piece of the pie via the sales tax when it comes to selling marijuana legally. That'll be handled by private interests, small businesses and corporations, not the federal or even state governments. I can't speak about Turkey (your home country), but that's the way it will be in the US. I can honestly see why you think this way, seeing how Erdogan would definitely take over everything Putin style if he chose to legalize pot in Turkey. Then he'd find a convenient way to funnel all the proceeds from the state monopoly to himself and his family members. Sounds about right, doesn't it?
Literally the one thing I fear about marijuana legalization is an excuse for police in various parts of the country to step up their arrest quotas for other things, in order to meet their municipal and local department's expectations on top of the soul-crushing and insatiable demands of the for-profit prison system. I'm not so worried about the predicted Great Doritos Shortage of 2017, as presaged by Vanoi above.
I'm glad that you couched this in such a way that anyone who played Rome: Total War would instantly understand it. Repped.
Compared to whiskey and hard liquor (which trashes your liver, severely reduces judgment, and could potentially kill you with alcohol poisoning), marijuana is about as consequential and damaging as having a papercut versus amputation. If you smoke too much marijuana you'll kill a decent amount of brain cells, while temporarily becoming apathetic, lazy, giggly, and spaced out/unable to focus or concentrate very hard on things. If you drink too much alcohol, you'll also kill brain cells, but you'll also most likely kill yourself via poisoning. Or worse, you could get behind the wheel of a car blackout drunk and run over a bunch of schoolchildren. On too much pot you'd probably be pressing the brakes every ten seconds out of paranoia/too much caution.
I fail to see the comparison in that. They're basically incomparable in terms of the level of danger.