I think Russia is the wrong place to look for what European countries will and won’t do.
On the whole the EU project, and the approach of tight economic ties across the continent has been a huge success.
Until Ukraine there hasn’t been a war in Europe for 75 years. Before the EU and the drive to economic integration, Europe had been in a state of almost perpetual war between the different states. Even today the economic integration has made war between most European states unthinkable. Nobody is worried about the U.K. declaring war on France or vice-versa, something that almost habitual before the 21st century.
Russia is the anomaly here, the one case where economic integration didn’t prevent war. But just because the approach isn’t 100% effective, doesn’t mean it’s worthless.