I think this period in existence will mark the beginning of the end. A period in time where the human life becomes worthless. This, in my opinion, is inevitable. However, thinking about this deeply, man cannot exist in a void, thus, if we eventually reach this period in time I think humans will create new set of problems for themselves. How this will be done I am not sure.
To the question: what will happen if one is no longer needed? Well, We've seen examples when people lose their jobs and feel no longer needed in the society. They opt for some form of gratification: drugs, gambling etc. This goes to support my point which is that a life cannot exist in a void, something must fill up the space.
Despite what we say, we need conflict and complication, problems to solve. The issue is that as the crush continues, less and less are able to solve the problems we face until some point, nothing can be done.