Salary is a range because experience and skills are a range.

Employers are willing to pay more for someone who can hit the ground running and contribute meaningfully to the team's output in week 2 vs someone who has the basic skills and a couple years experience but will need months to come up to speed on industry-specific knowledge.

But "week 2" people are hard to find, so they often settle for "months" people just to keep work moving along.