Well, this was early in the war, when everybody was green. And, they believed it when they were told they'd always have plenty of wagons for the heavy stuff. I doubt many of these lasted a month in the field during campaign.
Remember wayyyy back, reading Elisha Hunt Rhodes? Description of what men thought they could carry was awesome- still laughing at his description of the mother who rushed into their column as it marched from town and threw him an umbrella.
Ermm yes I think our now version on a slow cooker is much better !! And even then smelling food cooking all day makes you hungry all day .. so the thought of being starving and needing food when sick is just totally unpractical for them.. looks like an almighty contraption to use and cook with!