War is stupid and stupid expensive.
Each Tank costs as much as $5 million dollars....that's like a luxury mansion complete with an indoor swimming pool, 4 car garage and elevator. And as soon as a guy shows up with a rocket that costs as much as a brand new high end pickup truck or new corvette ($100,000) It's toast.
Not to mention the bridges over rivers and the destroyed train stations. (Which will be needed later) And the farms which aren't producing groceries....
So yeah....and yet....all these world leaders claim to be smart. Maybe this is some form of new math...