First of all, economies should, in principle, accept adjustment through market forces. Rigidity can lead to a build-up of stress in the system. Many words have already been spent on this subject, and I will not repeat them.
This was because the response of consumers of oil to a decline in its price was to consume more – not just more oil but other goods and services as well, using the higher real income afforded by lower oil prices. It was thought that this outweighed the negative effects of spending cutbacks in oil-producing countries.