Melodi
Disaster Cat
The real problem was World War I when a similar happened with the draft because so many recruits from the inner-city immigrant areas were so malnourished from starvation and disease that they did not qualify. That started the school lunch program in the United States, as the problem was large enough to be seen as a matter of national security (the real kind). It also resulted in a similar "class" issue I mentioned in my first post. Farm more "corn-fed, midwestern, farm boys" qualified (and died) during the First World War (from the United States) than those of urban and primarily immigrant families.
That helped fuel a rise in anti-immigration sentiment that would look familiar to many people today.
The kind of "damage" talked about both during WWI and today is the sort of thing you can't "toughen out" of people. Sure, you can throw them into a 25-mile hike with a 100-pound backpack, but if they fall with a shattered hip after 15 miles (today) or collapse from being too underweight to carry the load (WWI), it is a waste of time and money to train them. Then, we must discharge them and pay their medical expenses, perhaps even lifetime disability, if the injury results in a total disability.
In World War I, the damage was done in childhood through starvation combined with diets that were mostly cheap carbs and few vegetables or fresh meat and dairy. Today, the problems are malnutrition (and skeletal damage) from an ultra-processed diet and a lack of exercise (not just PE, simply not moving around much) that results in brittle bones, no stamina, early onset diabetes, and other conditions that can make even boot camp beyond the ability of their bodies to handle.
What may happen is what Israel did with their High IQ/High Functioning Aspies, which is to come up with a separate form of "National Service," which might or might not be military. But it would allow these young people to train and perform duties that they CAN do, especially those with better educations and skills who can do things like IT work or work in supplies and maintenance but not be able to physically perform well enough to get through even the modern and modified boot camps of today.
Isreal has compulsory service, and they had three choices with the Aspies: Give them medical exemptions, Keep trying the old way (and end up shooting some of them, or have them in prison), find a way to train them enough to do their jobs and then let them do the tricky types of "mental work" that they could do."
I am not saying that NO ONE from Generation Z will qualify or be able to be pressed into shape. I am saying that people with more direct experience than me with the issue are telling me that a large number will not be. That brings with it all the problems you had during WWI, but only with modern social media to ensure everyone knows about it, and families of young people who qualify will be upset that much faster.
