I guess I should clarify why I asked, becuase I admit it does sound like I think it's all about religion; Mecca is a place of pilgrimage, so in a way whoever controls Mecca has a lot of foreign, political and religious influences placed upon them.
I dunno if I got this right but it seems to me you have the impression Mecca runs similar to the Vatican. There's no Pope-like personality for Mecca, both political and religious influence wise. The place matters much more than the man. The title of the king of Saudi Arabia known in the English speaking world is "Custodian of the Two Holy Mosques" and direct translation from Arabic would make it "The Servant of the Honorable Mosques", so in Islam the person who rules the land of Mecca is regarded as a trusted guard who's ruling comes from the rules of Islam and Muslims are required to remove him of that position if he disregards the rules or uses his powers unfairly.
So whoever controls Mecca is still bound by rules. In other words they can never do anything radically different than what they do now.
Like for example the ruler of Mecca can't ban Muslims from any country from coming to Mecca to go to Haj (main Islamic religious rituals in Mecca).
He can however issue a decree of an all-out war against a threat to Islam or Muslims. But in today's world that order won't be carried out unless it's unmistakably evident that it's the only way. That's Jihad.
He can't tell people it's okay to drink alcohol or have premarital sex or anything that Islam has rules against.
Most Arabs -especially Egyptians- are highly critical of the Saudi monarchy and don't take them as a source of religious or political guidance.
Hope that came closer to what you were asking about.
And what, do you think, would happen in Saudi Arabia if the oil dried up? Or, I should say, when (either countries move past it, or it dries up). The lifestyle couldn't be afforded.
I really don't know about that but I imagine it as an almost post-apocalyptic world for them.
Mecca is a never ending source of religious tourism for Saudi Arabia because of the Haj month and Omra (also religious rituals) through out the year. I imagine when oil runs out -which is pretty far in the future if you ask me as an drilling man- that the tourism will be their main source of income. But it probably wouldn't be enough for them. I really dunno.
The running joke among Arabs is that they were shepherds before the oil and they will be shepherds after the oil.