Primus: before 2001, most Americans didn't care about Arabs one way or another. If they thought about Arabs, they probably thought rich oil sheikhs, Bedouins, or possibly Lawrence of Arabia if they were particularly well-versed in cinema. The 1.2 million* Arabs in the US were just like any other Hyphenated-Americans, distinguished primarily for living in Michigan. About 60% of Arab-Americans are Christian (mostly but not exclusively of Lebanese extraction), with about 30% Muslim and 10% Jewish (unlike Israel, where a Jew is by definition not an Arab and an Arab not a Jew, Jewish Arab-Americans historically had no problem so identifying).
Let's say that Steve Jobs emphasizes his identity as Arab-American. He funds community centers, cultural celebrations, provides scholarships. What's the result? Probably not a whole lot. It's possible that Arab-Americans in their late 20s and younger would have a bit of a reputation for majoring in Computer Science and Electrical Engineering (if that's how he focuses his scholarship money), like Indians do these days...but that's probably it. Steve Jobs was not a huge cultural icon yet.
Now, 9/11 - Arab Americans are villified. Steve Jobs spends millions on slick ad campaigns emphasizing that Arab-Americans are Arab-
Americans, same as anyone else. Hopefully, this will result in less crazy Arabophobia, but it could also backfire. In fact, the biggest effect I could see is if the ad campaign backfires, and Steve Jobs ends up irreversibly linked with Arabs - in the worst possible way. That could butterfly all kinds of Apple stuff, potentially changing the face of mp3 players, smartphones, and digital content purchase. Still, I suspect that the most likely result is that Arabs are marginally less likely to get heckled at the airport. There's no chance in hell that it's gonna stop the invasion of Iraq.
Come the Arab Spring (assuming it isn't butterflied

), we might see a Jobs-motivated push to increase American awareness, which I guess could lead to earlier and/or greater US intervention - particularly in Syria.
*Per the US Census. The Arab-American Institute claims 3.5 million