Just as a matter of logic, you can't prove wrong a rule of thumb that admits exceptions by pointing to an exception. There can always be reasons why, despite economic integration, other factors take precedence, e.g. perceived existential risks can push countries into war despite foreseen economic shocks.

In the case of Russia, while there were subtantial sanctions, it was still trading natural gas to the EU, and I believe they still are. China and India also helped Russia (and themselves) tremendously by buying huge quantities of discounted hydrocarbons, and I think it's plausible that there were indications before the war that such deals would be available.

As an aside about drones, a striking number of new companies established over the last handful of years in several European countries are military drone specialists. By now it's quite obvious why. In the future I guess there'll be a new slew of companies specializing in counter-drone tech.