What determines your starting salary (in the range)?

Honestly, I saw posts for assistant profs and they often say eg the starting salary ranges from 90k-130k. That’s for one University- they specify this range for assistant profs.

What makes the range so large if say the people are compared to with similar experiences?

Is it the person’s CV, Research area, publications or what? What if the person comes from a prestigious uni like Ivy League versus a lesser uni?

How does one get the top range of things?

Note: I’m asking about the same field same uni- the differences within.