Suppose a large nation decided that after a large nation was beaten down to below normal nuclear levels, he decided to keep fighting without nukes. Also suppose he has a full battery of military wonders, and has a stable trade circle that is secret. Supporting a full, nonnuclear, no navy army would require very few bills, somewhere around 50k in bills adding the rest of the bills would bring us somewhere around 500-600k including infra at 1k and improvements. Assume normal war expenditures per day is around 2mill. With a full complement of improvements and wonders, collections would be much greater than under normal circumstances but it probably will not create enough to fund continuous war especially if they have guerrilla camps.
Here is where it gets interesting. War is the only way that nation is going to survive unless they are aided. Guerrilla camps decrease income by 40%. However, if the nation has guerrilla camps, barracks, and a pentagon, their ground attack chances are increased by 245%. If they have an WRC their tech bonus is even greater. Now, if they are engaged in 6 wars they are going to win a greater portion of the GA than they are going to lose. In those ground attacks, assuming that they are fighting nations with at least some war-chest, they are going to get enough money to fund the war. So the only way they are going to survive is through continual war or it is bill lock.
While at war, we can assume that they have fairly high air force left over from when they were larger, as well as CM improvements. If at war with six nations, that single nation can deal out 420 infra damage to six nations, from those two types of attacks alone while sustaining only 30 from combined CM attacks.
Numbers were only estimated, I don't know exactly how much everything would cost at that level anymore. Feel free to argue my points.