[SauronOfMordor]

unless you win the ideological battle, the war will never end

As Jerry Pournelle puts it: "Ideology counts. But it does its counting with a sword".

Military victory gives the ideological adherents the sense that they are on the correct side. Humiliating and complete defeat makes them question ideological infallibility

[Luis Gonzalez]

Military victory against whom exactly?

Convince me of the veridity of your claim by painting a scenario whereby there would be no more Christians in this world as a result of a military victory.

Your claim fails to consider one of the most basic facts about extreme religious fervor: it views death in the hands of an enemy to the faith, as an ultimate victory.

That's constant in Islam as well as Christianity.