I hate to sound so negative, but I truly believe that we will see autonomous or very nearly autonomous, ground-based combat units in less than a century. The flying drones were only the beginning of that battlespace technology. There is a huge interest among certain groups of people in the US to be able to wage war with little or no "friendly" casualties. I know it's cliche to say it, but imagine one of those Boston Dynamics robots, except it moves 20x faster, carries a firearm, and is capable of acquiring, targeting, and shooting you in sub-second time.

The pentagon and politicians know full well that the public doesn't tolerate flag-draped caskets coming home for very long before "war fever" ends. And I really can't imagine a draft would really happen in the US unless the continental US was somehow under direct invasion. There will never be another Vietnam war with high conscription and high death toll.