The Forever War?

George Friedman opens his post with a list of the ways that wars end:

1. A war ends when one side lacks the material to continue. Germany’s campaign in World War II ended when it was unable to produce and field the weapons needed to fend off the Allied powers.
2. A war ends when one side’s morale is exhausted – when soldiers and civilians are simply unwilling to bear the burden of war, even if victory is possible. This was the case for the United States in the Vietnam War.
3. A war ends when there is no hope of a radical increase in military power, and when foreign intervention is impossible. In WWII, Britain persevered knowing it could not defeat Germany but reasonably expecting an American intervention.
4. A war ends when the consequences of defeat seem tolerable to civilians. In World War II, the Italian public saw Allied occupation as a preferable alternative. (Conversely, nations will continue to fight when the cost of defeat is catastrophic.)

concluding that the war in Ukraine is likely to continue for a long time:

Over time, then, the sense of the impossibility of victory will trigger peace talks, but not until reality forces it.

I wonder if the war will continue until there aren’t enough Ukrainians between the ages of 15 and 45 to maintain an organized resistance.