Except that oil accounts for all of 1% of US electricity generation.

http://www.eia.gov/tools/faqs/faq.cfm?id=427&t=3

Yes but PV is one quarter the electricity production of even petroleum.

Natural gas is a petroleum product.

It's often burnt off because the quality / quantity / opportunity costs for capture and resale are often insufficiently compared to other extracted products.

That's not really true anymore.

What evidence do you have? Excess gas is routinely burned off nearby oil derricks to this very day because it's not cost-effective to capture for resale.

Oil is only going to fall long enough for Saudi Arabia and the US to bankrupt Russia, though (and they're pretty far along into it already).

Or for Saudi Arabia to bankrupt US fracking companies.

A few of the companies might get shaken out, the ones stuck with use-it-or-lose-it land rights, but the rest can shut in production easily enough and wait for prices to rise again. Drilling a well with fracking is really cheap and incredibly fast which makes the industry fairly resilient to changing prices.

Or for Saudi Arabia to forestall the re-emergence of Iran.

There are several pipeline projects in the US and Middle East that are in flux, and this would be an opportune time to kill them.