When WWII ended there was a large combat experienced well of manpower to make the draft function exceptionally well. The Vietnam War soured the draft for many reasons. The public's lack of support for the draft forced a huge increase in funding to meet recruiting and retention needs of the professional forces. The result was a reduced size professional military that costs way more and no longer able be a deterrent to the likes of Russia in Crimea, China in the South and East China Seas, North Korea, global Islamic terrorism, etc.
There is not a country in the world that pays its troops what we do. Call up an infantry National Guard brigade for combat and it would take at least a year to be combat ready. They are undermanned, some units exist only on paper, while lacking equipment and training funds. The drafted troops train up for Korea was less than 3 months. While we are playing Whack-a-mole around the world and our allies all but bankrupt, our enemies are spending far less of their GDP and gaining in power and global control. They all take advantage of the draft to keep costs down. China can pay 9 of their lowest ranking soldiers for the cost of 1 US soldier.
The draft is no panacea and clearly has its minuses, but we can never pay for the professional military size needed to do what we did on two fronts in WWII. That is a economic reality.