Interesting article. One question that it missed is how Russia might use this leverage if they are planning on losing the American market for the RD-180? I can see them assuming that there is no long-term gain from keeping ULA and the US gov happy given current US-Russia relations and SpaceX's development schedule.
You ought to understand that what Russian officials are publicly saying and what they actually intend doing are quite different. Russian bureaucracy is every bit interested in supplying engines while they bring back significant cash. To stop doing that is directly hurting their abilities to enjoy life outside of Russia - which they aren't prepared to lose.
It's an interesting dilemma. If the Russians play hardball, it might cause the US government to directly fund an engine replacement. It might also cause the US government to pay SpaceX to make Falcon Heavy available sooner. Both of these remove Russia's leverage in the future.