In reality, it could have gone either way. So easy for market followers to dismiss any incentive that OPEC may try to implement but the true resolve was there and members fell into place and with that, Russia came too.
The success overtook the mistrust between leading members and non-OPEC producers with the realisation that the cartel and its competitors may never again have such an opportunity to unite for a common course and share out the spoils of the market. How long it will last for is another matter and only time will give the answer.
Each member country has accepted an output ceiling with Saudi taking the largest cut followed by Iraq and Iran. Libya and Nigeria have been exempted and Indonesia which had just rejoined OPEC has once again left the cartel. The total cut for OPEC will be 1.2mbpd based primarily on October figures but not effective until January and this will be the first cut since 2008 but the next surprise came with the announcement that Russia would actually cut by 300,000 leaving other non-OPEC producers to be responsible for the remaining 300,000. Supposedly OPEC members have signed up to the deal but it seems to be contingent on Russia and other non-OPEC producers formally signing too, to make the deal effective.