Cartels gonna cartel.
The basic premise of a cartel is to restrict supply, in order to drive up prices for the cartel's goods.
OPEC's global influence over Oil & Gas seemingly waned in the 2014 / 2015 oil crash. Yes, I was on the bandwagon back then that questioned the relevance of OPEC in the future. Seems I was wrong.
Now, OPEC + Russia + Oman and other countries are tentatively agreeing to maintaining the cuts in production that were started at the beginning of 2017.