If the Arab nations were to boycott sales to the US, then they'd have to find new customers to buy their oil or face a huge monetary crisis in their own countries. They have virtually nothing anyone else in the world wants but their oil and that makes up virtually all of their income. How well could countries like Saudi Arabia handle losing a big percentage of their national income?

So, they'd have to sell their oil to someone. For other countries, they could well see their oil prices go down due to supply and artifically reduced demand. More oil would be on the market because the millions of barrels we import each day would stop flowing. Some of those countries could well turn around and resell the oil to us, a win-win situation for them.

If they were to boycott the US, then pressure would be brought on those Democrats who keep blocking US oil development. They might well end up looking for a new line of work. If the prices do go up, then you're right, alternative sources suddenly become a lot more economically viable. The Arabs know this, as illustrated in this article in the Arab News.

"If import cuts were to occur in any of the major oil-importing nations, among the OPEC, it will be the countries in the Middle East which will be singled out for segregation."

This article is looking at the question from the point of view of the US reducing our imports rather than the Arab nations reducing their exports. They believe they can easily find new customers due to economic growth around the world. If we can become more energy independent to the point where we can reduce our imports, then our economy would still be strong.

However, if they cut sales to us, then it would probably hurt our economy like it did in the 1970s. By extension, that would also hurt the economy of other countries around the world as our economic slowdown over the past year has. If that happens, then other countries would have a hard time buying more oil to make up for the lost sales to the US. In the end, that would almost certainly mean less money for the oil producers, something they can ill afford.