I can only speak for us (Germans).
You are right, we (mostly) do still "home cooking" from raw, fresh ingredients every day like e.g. "Pichlsteiner Stew"
One great thing we brought over from the US, slow cooking

Et viola
or "Rouladen"
Fill with vegetables and mustard
So this is German "home cooking" how we do it (almost) every day.
BUT, e.g. our troops in Afghanistan don´t get this either. In the German Army, they must offer you the same (sanitation, medical and hygienic) standart like back home. As there are non of them in Afghanistan, ALL foods must be delivered from Germany all the way down. So there is a limitation on what you can send. So e.g. egg´s don´t make it this longs this far. We had once a food poisoning in Masar-i-Scharif in 2011, cause by the ground beef sauce of the Spaghetti Bolgnese dish. Afghans are not used to wash their hands after using the bathroom...
You don´t have this problem with rations.
In the German Army, you get fed until there is a real (field) kitchen established. Rations and field kitchens (B-rations) don´t need any refrigeration , so they can´t spoil.
So feeding the troop is always a compromise of circumstances and nutrition and I think, the Americans have one of the best, most advanced feeding program of all Armies in the world.
Even our´s start to replace ours to regular, grocery items...
