No, it really isn't. Even in peace time you'll need most of this: You need safe food and safe water for yourself and a chance to consume it. You'll also need

No, it really isn't. Even in peace time you'll need most of this: You need safe food and safe water for yourself and a chance to consume it. You'll also need water for bathing etc if you can to maintain comfort. To be combat effective you need a lot of energy. You'll also want to be comfortable so let's say 2l water for drinking and 50l for washing if possible. Food - at least 4000 calories per day. Now you need to do something and that will require munitions and weapons. A tankie will require a lot of fuel, bits of track, lubricants for all the funky stuff. They'll need shells of various types - AP (anti personnel - basically ball bearings to kill people) and APDS types (armour piercing discarding sabot) and the other more modern fancy types with nastier purposes. Anyway - quite complicated and expensive too. A tank out of fuel and shells is just a quick kill for the enemy. Logistics is not that simple and we see this in Ukraine.