Most people at my age have sense from the very beginning that they will have future , or not. But nobody quits even they have such senses. They still go into there and experience love and sxx, including me.( i'm only love no sxx.)
I don't know how to explain this. Of course, there are also cases ( a lot or even majority I don't know, I am not sociologist) that after long time drag, that the "no future" become "have future or marriage".