ya the rise in the stock price of Facebook had modified the 19 billion to 22 billion. And Facebook used this approach to eliminate any further reduction in its user hours (number of hrs used by the user) , but i think Facebook might use the database of the users in different ways.

Companies now a days price the product not based on a fixed profit margin but on the perceived value of the customers. As apple knows that its customers are ready to pay a huge amount to obtain its product , it keeps its price high. As an individual if you ask me  I prefer android phones over i-phone.

Not exactly , the best example is a cigarette pack even after the fact posted that smoking it will cause lung cancer does not reduce the preference for it by large extent.