Certainly you believe that everything has a cause (else you would have no reason to believe that an end would be immanent). Whatever it is that has been causing homosapian to continue existing would have to be removed or defeated in order for homosapian to stop continuing. To speculate that homosapian is going to soon end implies that you see the cause of his continuance going away or being defeated.
So what is it that is causing homosapian to continuing existing in the first place?
You can’t just look at the fact that people keep pulling water out of the well and presume that soon the well must be empty. You have to also look into what is filling the well from deep below the surface. It is the balance between those that determines if and when the well goes dry.