Their concern is for the long-term power of the Opec cartel, which used to be strong enough to set the price of oil. That never will be true again unless they can drive the (mainly American) frackers out of business.
Saudi Arabia and its allies hope a prolonged period when the price of a barrel of oil is lower than the cost of getting that barrel out of the ground by fracking will ruin this new industry and bring back the Good Old Days. Dream on.
The Saudi strategy won't work because some 98 per cent of US crude oil and condensates has a break-even price of below US$80 per barrel. Indeed, 82 per cent of American production would still be turning a profit at US$60 per barrel.
Even with its huge foreign currency reserves, Saudi Arabia probably cannot afford to keep the oil price low enough for long enough to break the American frackers. (Its own break-even price for conventional oil is US$93 per barrel). And the Iranians, Nigerians, Venezuelans and Russians, who depend on oil revenues for half of their national budgets, will be screaming for higher prices before they face riots.
So this is not a transient event; it's a revolution. The Organisation of Petroleum-Exporting Countries (Opec) came into its own when the US ceased to be the dominant global producer in the early 1970s. With the re-emergence of the US as the biggest producer, Opec's clout is bound to shrink - so oil prices will probably stay well below US$100 a barrel for the foreseeable future.
This will be a boon for countries that depend on imported oil such as India and China. It may also liberate the US from its compulsion to intervene repeatedly in Middle Eastern disputes that are really none of its business.
And it may be a disaster for repressive and/or corrupt regimes in countries such as Russia (break-even price US$105 per barrel), Nigeria (US$119), Venezuela (US$121) and Iran (US$140).
It also means worries about "peak oil", and the underlying calculation that the world had only about 40 years' worth of proven oil reserves left, can be set aside for a while. We are already up to 53 years of reserves, and we are finding new oil faster than we are using existing reserves.
Of course, a broader view would find little reason for rejoicing. Our global civilisation depends on fossil fuels for 85 per cent of its energy, and our annual emissions of carbon dioxide and other greenhouse gases are still rising.
Just another 25 years of that will deliver us to the "point of no return": 450 parts per million of CO2 equivalent in the atmosphere. That would raise the average global temperature by 2C and trigger natural sources of warming that it will be impossible for us to turn off again. Runaway warming is not a happy prospect, so it is unseemly to celebrate the news that we have even more oil to burn - and cheaper oil, at that.
On the other hand, it would be entirely appropriate to celebrate the news that other new technologies may open up a better escape route from fossil fuels. Solar power, wind power, nuclear fission, and hydro power all have a role to play in that task, but the Holy Grail for half a century has been fusion power. It may be much closer than we thought.
Gwynne Dyer is an independent journalist whose articles are published in 45 countries.