There are hundreds of years worth of oil deposits (possibly more) even at current usage rates. "Selling all the oil" isn't in the realm of possibility.
As much as necessary, sure. Oil it turns out is pretty useful in many different industries and contributes to higher standards of living for the vast majority of the world. It isn't some inherently evil technology or resource. Still, it's going to take decades to transition to electric regardless of any breakthroughs in the meantime.
