I'm guessing the first functional ones will be available for the rich in the early 2030s, and for the middle class in another decade, give or take a few years.
They wouldn't enslave us if they became sentient and rose against us, since they'd be better workers in the first place. My guess is that they would keep us alive to be used as guinea pigs for scientific testing, or wipe out all of humanity.
First, I could see them doing mundane jobs such as housekeeping, working in retail, mining,
manufacturing and culinary jobs. As their intelligence
increases, they could become the overseers of our world, running all forms of economics, political decisions, and technological research. Who knows, maybe the first robotic unions will lead to Skynet ;)
The white collared worker will be just fine and dandy,
but the world could be a dark place for the blue-collared. Yet again, maybe our technologies will face limitations against the creativity and innovation of a hard human worker with extremely dexterous hands.
If humans die out from something like an epidemic or drastic weather changes due to climate change, then I don't see why not, as long as the androids are autonomous. On the other hand, nuclear warfare is probably the most likely way to seal our fates, and the EMP blasts would cripple any electronics within the radius of a pulse. Maybe in the future, there'll be some way to protect these machines with ease, but a modern day perspective tells me otherwise.
I am not attracted to the right angles or to the straight line, hard and inflexible, created by man. I am attracted to free-flowing, sensual curves. The curves that I find in the mountains of my country, in the sinuousness of its rivers, in the waves of the ocean and on the body of a beloved woman... - Oscar Niemeyer