What’s behind the oil price plunge and the associated stock index plunge?

Russia refused a Saudi Arabia deal to cut oil production during the current drop in demand for oil by an additional 1.5 billion barrels per day. This would have been on top of the 1.7 billion barrel per day cut begun some weeks ago in response to reduced oil demand driven by reducing Asian and European economic activity.

That reduced demand has been exacerbated by the coronavirus’ panic-driven impediment to overall economic activity.

In response to the Russians’ refusal the Saudis cut their price of oil by $6-$8 dollars and have said they’d increase their oil production by some 2.3 million barrels per day. In essence, the OPEC-agreed limits on oil output are completely withdrawn.

This has added stress to the Russian economy.

…the Russian ruble ha[d] its worst day since 2014, down more than 8% against the dollar.
…
Russian authorities on Monday pledged to use their $150 billion sovereign-wealth fund to support the economy and said the nation’s budget can withstand low crude prices for a decade.

But at what cost, what trade-offs? Given Russia’s financial commitments/needs to support its occupations of Ukraine and Georgia, its drive to build up its military, its cyber attacks against Ukraine, the Baltic States, and elsewhere around the world, it’s part in the joint development, with the People’s Republic of China, of Siberian resources, and on and on, for how long can Russia’s monetary reserves last, really? How long until Russia starts printing roubles, and triggering dangerous inflation?

And: do we have the stomach for lasting longer and doing better than Russia?