The United States had over 200 million people as of 1973.
Israel today has fewer than five million non-Charedi Jews.
The idea that Israel can survive with a purely voluntary army is fantasy.
“And it did so with an all-volunteer army.”
That isn’t true. There was a draft throughout the 1950s after Korea and prior to Vietnam. This despite a population of 180 million as of 1960. It was only the population growth (with the baby boomers becoming old enough to volunteer for military service), the end of the Vietnam War, and the massive cuts in defense spending that accompanied the end of the Vietnam War that allowed the US to drop the draft in 1973.
By comparison, Israel today has fewer than five million non-Charedi Jews. The combined active duty armed forces of Saudi Arabia, Egypt, Turkey, and Iran constitute two million people, and I would trust none of those countries! The idea that Israel can survive with a purely voluntary army is fantasy.