I've used solar PV since 1990 and am typing this message with solar generated electricity.  It's great but it's not going to replace digging up a hundred million years of stored energy.  We are all going to have to learn to live differently whether we want to or not, which is far more important than modest improvements in energy efficiency that are ignored by most of the society anyway.  (How many buildings are built in Eugene with passive solar design -- almost none.)

If the resources have been extracted, more demand does not make them magically appear.   

The Saudi government, like other "one crop" countries, has been badly damaged by the drop in oil prices that have wrecked their governmental budgets.  They're torn between wanting low prices to diminish drilling for expensive oil but wanting the revenue from selling their cheaper oil at high prices to fund their society.  Meanwhile, they produce almost no food, which is not good in the long run.