No matter how good a product may be, regular investment and innovation are needed, especially in competetive industries. Failure to do so leafs to rapid decline.
You are right of course. The orientation on EU and withdrawal from Russian trade agreement was a big mistake at the time. They should have known they won’t sell aircraft engines or nuclear reactors or even Chevrolet cars in Germany. And since they have no market they have no revenue to keep their base up to date or at least to pay their workers.