If this is true (and I believe it is), it does not logically follow that destroying physical symbols will stop Islam (and will probably not even slow down Satan and the forces of spiritual evil).
That being said...I don't know what the answer is.
You said -- "If this is true (and I believe it is), it does not logically follow that destroying physical symbols will stop Islam (and will probably not even slow down Satan and the forces of spiritual evil)."
Well, I say this not because I hold those symbols as powerful or somehow lending power to their actions (i.e., Islam). It's basically because the Islamic world seems to hold these things to a level of basic, core, and foundational legitimacy of their religion. You see, they have to destroy other "symbols" from other religions, in order to make theirs paramount. They've done it with Christianity and with Judaism. That's why we've got the Dome of the Rock on the Temple Mount.
But remember, with Christianity (and Judaism), we've never made these things the foundational element of what we believe. The Muslims have with theirs. It's the method for their destruction.
They basically could not tolerate having anything there (like the Jewish Temple) which would even be "alongside" theirs. That would be too much of an insult to their idea of legitimacy.
So, since the Islamic world has vested so much into this kind of legitimacy, they have made themselves vulnerable to their own collapse, using the very same reasoning that they use for other religions in destroying their symbols.
Don't you see? It's their own failing. It's also the solution to the Islamic terrorism problem.
As for Satan and the forces of evil, no..., this will not stop Satan. He will continue on with all his ploys and machinations. However it will stop Satan from using this one tool in the manner it's been used up to now.
Only God will stop Satan. We know the end of that story.
You also say -- "That being said...I don't know what the answer is."
Well, the answer is always the Messiah of Israel. There is no other. We may be suffering with this type of terrorism for years to come, until the return of the Messiah. And, in the end (this very short end, at this point in time), it will be solved totally by the God of Abraham, Isaac and Jacob, through His Messiah -- whether anyone wants to recognize that now or not.
Regards,
Star Traveler