Russia wants to tip the balance of power in the ME. The crap Erdogan has given us is from Putin sweet-talking him. Turey thinks it no longer has use for us. That's how Turks are.
Russia already a monopoly on European oil. Imagine him getting a land pipeline from Iran to Moscow. If that falls in line I doubt it would take a lot of convincing the pro-Shia gov't in Iraq to get on board and they have a land pipeline from Iran to Syria. And I'm not making this up. It's in one of the threads in the ME forum.
He could economically strangle Europe. Something the USSR was unable to do.