Their oil reserves are enough to replace the ME too. All they have to do is double production and provide oil at a flat rate that makes them enough profit, which is $60-70 and keep prices so low that the ME's economy is taken out.
Basically, you can't take only half, it's all or nothing. Even the ME has to be made into a pariah region for that to happen, alongside Russia. And there's enough room to achieve that since the GCC is composed of monarchies and are easy targets for sanctions. It explains why the Saudis are thinking of switching away from USD. After Yemen and Ukraine, it's clear to them as well that the US won't protect them.
That makes no sense, why would they have to replace the Middle East too?
The US absolutely can protect them, but there are rules as regards engagement of a country with 2,000 nuclear warheads. In Ukraine Russia's bluff works because it's close enough to their doorstep for there to be doubt that the bluff is fake, in Saudi Arabia that is clearly not the case. Yemen is not the US's job. And, as with Ukraine, only a small section has troubles.
You have to play the game tactically, at the moment Putin's Russia is killing itself. If Putin could leave and hang on to power at this stage he would, but he knows his days are numbered if he kills 20,000 Russian soldiers for a loss, by continuing the war he hangs on for longer, but there is a limit to how long he can do that. At this stage he has already lost, he's basically moving his king back and forth for a while before the inevitable checkmate.
Take the Chechen Wars, the population of Chechnya is only 1.4m, and it was in Russia, and the Chechens had no help, that took him >13,000 lives and two several year wars and 15 years total plus insurgencies. He's up against 40m here with lots of help. Because of Georgia and the annexation of Crimea he thought Ukraine would be a pushover, but as Arnie would say, "he thought wrong."
Another effect is that Russia appears properly weak militarily. They lost the battle of Kiev quite embarrassingly and less of their neighbours are likely to be scared of them now. They also lost all their remaining apologists and sympathisers within the EU. They've destroyed themselves militarily, economically and politically in one ill-conceived and unnecessary move.