[ACOK 2.2] So has anyone had an invading faction actually be successful?

Targaryens were defeated in about two weeks, shortly thereafter the Free Folk were defeated.

I did both those quests to destabilize the realm so that I could make it easier for my character to take over. It didn't dent it at all, no one noticed. The only thing that has changed is that Dorne is at war with literally everyone now.

Has anyone actually had the invading faction be successful?