Are you confusing Tesla with Uber? Uber needs self-driving cars to justify its valuation. Tesla doesn't. It just needs production volume. If anything, very near-term self-driving cars might be bad for Tesla because it would reduce aggregate demand for cars.
No, although I think Uber is in dire straits itself. A lot of laypeople buy Teslas not just because they are electric but because of a general feeling that they "are the future." The self-driving dream goes a long way towards driving this consumer sentiment. If self-driving peters out in the way I suspect it will, Musk/Tesla begin to lose some of their luster. If traditional car brands can bring in affordable electric cars which also look good, what will Musk have left? His image is necessary and part of that image is placed in self-driving.
I think the current capabilities in 'self driving' are already driving a lot of attention and sales. Even if it 'peters out' in a few years with only refinements on the current abilities, people love the idea of a car that can park itself, come when summoned, handle the drudgery of stop-and-go commute traffic, and predict/prevent some accidents.
Those features alone are good enough to make a $35k car very desirable.