If you can go to war at 18 you can play a professional sport or drink imo.
It's been proven by numerous players that playing out of high school is possible so let's not say age or maturity is an issue. It all comes down to making a better product though. I would compromise and say NBA Draft and d-league is open to players 17+. NBA 20+ so if a kid needs $ he can play professionaly and help his family. He does not have to go through the farce that is one and done. NBA needs to stop being cheap.

SO greatly increasing the chances that you kill someone or are killed yourself is on the same level of competing at the highest level in sports?
Not disagreeing with you, just pointing out a poor analogy.
Lol that is the definition of a bad analogy. How do you get killing or being killed out of that. It's fighting for your country and having the maturity and tools to take on other men that you are up against no matter the age of those men in battle. If we think 18 years can handle that then they can handle alcohol or sports.
Except that there is a ton of physical and mental training. I have a bunch of 18 to 20 year olds that work for me, and no way are they mature enough to drink(even though they still do and try to call in sick sunday mournings, and grubble when I say they need to bring in a doctors notice that they were indeed sick if they want to get back on the schedule).
In the army it's 27/7 training and you're closer to 19 before you even get considered to ship over. Plus they are supervised most times with in walls or an area. So the temptations of the out side word doesn't effect there training. And your taught respect, which goes a long way.
NBA the kids get a ton of money with little to no guidance and are free to do what they want out side the few hours a day they have to practice. Some kids get it and work hard, but many don't, not to the point they should any ways.
Now if you want a minor league, Im down for that. But it should be intense. It should be in confined areas for weeks at a time with a few days of recreation in between. And you put in the two years, then you can enter the draft. Go to two years of college, enter the draft. But schools should give players a free 4 year ride even if they leave after 2.