Worth appreciating the economic dynamic the article is based on:
https://en.wikipedia.org/wiki/Resource_curseBasic issue is that when a government can fund itself using resource extraction, it does not need the consent of a nation of people who would otherwise make up a tax base, so they pay the army and police out of oil money to keep them in power, and the average citizen is reduced to a subject. Trouble is, if all you need for power is control of the resources, it's not like you need to spend on winning hearts and minds when you can seize the resources with a relatively small rebel group. Given the high stakes of oil/resource billions and the very low bar to entry for cheap rebellions to seize them, these incentives are a recipe for the political shit shows we tend to associate with some resource cursed economies.
The predictable effect of oil price collapse is that leaders can no longer guarantee those payouts to the people who keep them in power, and as a result, those people will replace them with someone who can keep paying them. This is described in the DeMesquita-based idea of the "Rules for Rulers" video (https://youtu.be/rStL7niR7gs), which is related to the article's closing line about leaders getting their peoples consent.
The "Arab World," is a diverse place with a variety of multilateral interests so there are more dimensions to the outcomes than this, but the most obvious risk is that China will prop up whoever they can control in exchange for oil, and the mid-east will become the field for an China/US proxy war. The next risk is that unfortunately, if Arab leaders are reduced to winning hearts and minds to stay in power, they may do it with appeals to religious radicalism instead of democracy, which will bring about another era of state sponsored terrorism, that again, invites war.
Nice that we're using less oil which is good for the planet, but there is the small matter in the interim of what is good for humanity. The people who lose in these conflicts are never the participants, but the ones caught between them. These people will form new waves of refugees from the conflicts that can bring additional instability.
The precise knock-on effects of an oil price collapse can't be predicted, but you can anticipate the change in downstream volatility, and find a way to become indispensable in volatile times.