While I'm not an expert in this area, it is also possible their cyber campaigns specifically target improperly defended industries. Attacking a target is much easier than defending one, that is true in every field and most industries don't take their cyber security very seriously. A cyber attack that is funded and sponsored by a large state like Russia is sure to find many victims. Most industries are easy targets because they have thousands of people who are not trained in to defend against even the most basic of cyber attacks.
And of course only the successful attacks make the news, the unsuccessful one are never reported.
There is an experiment in Russia that has been breeding foxes for over 50 years now. The goal is to understand how domestication changes an the physiology of an animal. They breed the foxes that show the most tame and docile behaviors towards humans in an effort to recreate the process of changing wolves to dogs.
On the flip side, they also breed the foxes that are most aggressive and hostile towards people. One day they will get too powerful and get loose...