I do not believe that Quora, Musing and other similar websites will become obsolete.

I think that computers and AI can give answers to factual or even technical questions (like how to solve very difficult mathematical questions), but they cannot give answers to life. And the bulk of the question on such platforms consists of how to live this life. Computers and AI cannot provide any personal experience whatsoever on say, how to cope with a child's death or similar griefs.

Also, they cannot provide their own personal opinions or perspectives on current events. This is because personal opinions are formulated from the accumulation of all the personal experiences one has gone through in his or her life. The way you think is shaped by your  past and your upbringing. 

Thus, it is my firm belief that we will never stop valuing the human touch which only human contributions to such Q&A platforms can give.