It's even hard to consider you a regional power in the region if we exclude your oil reserves, let alone a regional super power when Turkey and Iran are in the region. Even if we exclude Iran, Saudi Arabia is simply a joke in comparison to Turkey. Economically, Military, Scientifically, you're nothing in comparison to Turkey. so being a regional super power is only a delusion for you right now. Your military will lose to Turkey, in science you're a joke in comparison to, let's say, even Egypt. Economically only in the last 5 years your economy has been doing fine and that's because of high oil prices. Your GDP growth is really negligible in comparison to Turkey's GDP growth. Let's not talk about a regional super power again or you'll make yourself look ignorant.
About the first part, the USA had Iran as its first ally before the revolution and we all know how that alliance broke easily. If the USA dumps Saudi Arabia, there are still many other countries in the region like Iraq that can compensate for the Saudi oil. It just takes 5 years or so that they build oil refineries and build the necessary infrastructure to drill oil. This is while Saudi Arabia is completely incompetent to make its own oil infrastructure without foreign help. so it's you who is dependent on the USA, not the USA on you.
You don't control the oil prices in the oil market. That's another wrong point you made. We saw how hard you tried to keep the prices low as the USA wanted but you failed in the OPEC meeting twice this year. Venezuela, Iran, Libya(before Ghadhafi gets toppled) and other oil producing nations in the OPEC challenged you completely. Soon Iraq will increase its oil production to more than 5 million barrels per day and the Iran-Venezuela-Iraq bloc will be even stronger in the OPEC.
About Khamenei, he has never said such a thing about Saudi Arabia.