The demand will rise again once this virus is done with.
The saudis are losing money doing this (they have to eat into their reserves to fund the country). Russia at least has other industries, however small it may be.
Saudis cannot care less because they have about three times of Russia reserves nominally. In fact I suspect about five to seven times that, because Russia reserve structure is basically unknown. Saudis can certainly afford a year or three of having no income.
This is on top of the virus panic (which just cut any remaining tax revenues). Russia, Venezuela, Iran for that matter are done for.
EDIT: Which is why I think the whole OPEC+ deal went to the crapper. Middle East is able to weather this, others - not so much.
Arguably there isn't anyone like this in the rest of the world either, but I digress.
Our entire culture and urban physical infrastructure is built around a certain level of oil consumption. The current situation is temporary, the real solution is to replace the source of energy of fossil fuels. We are projected to have green energy be 30% of all energy consumption by 2024 with much of this effort lead by China.
The extreme central control and lack of freedoms that the western world hates so much is exactly what makes China so effective at protecting themselves against COVID-19 and saving the world from an energy crisis. We value freedom but the cost is too high.