It is more complicated than that. At some situations a few old/fat/stupid/etc soldiers could decrease the overall effectiveness of the unit. In too many cases, no soldier at all is better than a very bad soldier.
Sure, I don’t disagree that a very bad soldier can make things worse than by not being there, and the factors you mentioned have a negative correlation with performance, but I don’t think you can automatically determine people will be that level of bad of soldiers based solely on those factors, particularly age.
Especially since people still work at that age, even in physically laborious jobs.
Armies also tend to have more support troops than combat arms anyway.
It is more complicated than that. At some situations a few old/fat/stupid/etc soldiers could decrease the overall effectiveness of the unit. In too many cases, no soldier at all is better than a very bad soldier.
Sure, I don’t disagree that a very bad soldier can make things worse than by not being there, and the factors you mentioned have a negative correlation with performance, but I don’t think you can automatically determine people will be that level of bad of soldiers based solely on those factors, particularly age.
Especially since people still work at that age, even in physically laborious jobs.
Armies also tend to have more support troops than combat arms anyway.