LONDON — Back in the golden bubble days when stock markets were riding high and a barrel of crude oil sold for more than $140, there was no doubt which countries were getting richest quickest.

The Arab oil producers found themselves at the receiving end of a tidal flow of cash that they piled up in sovereign funds and investments round the world, while also enjoying an easy and hugely luxurious lifestyle.

Now things are different. Could the sharp drop in crude oil prices, combined with longer-term global aspirations to reduce oil dependence, lead Persian Gulf oil-producing states to reassess their priorities and development prospects?