You've got this normative halo around "intelligence". All intelligence is, is an agent's ability to satisfy its utility function.

>But if it continues to work on the paper clips and decides that they are still needed even after people are gone - how is that super intelligent?

That is the correct action if all it cares about is making paperclips. Creating paperclips satisfies its utility function. Fretting over the existential issues of creating paperclips long after the last piece of stationary was destroyed would be judged of negative utility.