There are two options: Either we have terminal goals that include "having a good time" and "living enjoyable lives", so that a pleasant life is good in itself. Or else we have terminal goals that are finitely achievable, and when we've achieved them we should shut down humanity as useless. In the latter case, we can throw out anything that doesn't advance us towards those finite goals; not in the former.

I think one may hold the first belief without advocating wireheading, in that our terminal goal may be "enjoy a wide variety of pleasant things that exist outside your skull".