I think the line of thought that economic (co-)dependence makes conflict impossible or leads to a more harmonious relationship is probably the gravest error in german foreign strategy. I think it's a reason behind both our relationship with russia and china. But it assumes a rational actor who's concern is the well-being of its people. Putin doesn't care for his people, he cares for power. He want's to increase his power, the stability of his regime etc. He might have employed the same flawed thinking to come to the conclusion that europe won't help ukraine if it's dependent on russian energy.

In reality, economic costs only become apparent after the harm is done. The greatest strategy crumbles if it is build on flawed assumptions.