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.

In purely theoretical terms I agree, but I don't think that's practical given that you be open to someone more or less experienced, and slightly change the role based on who's available. Experience-based salary ranges are everywhere, even in highly-regulated roles like the NHS in the UK. The key here is the low figure, which will let you know whether they might try to lowball you (presuming there's enforcement if a role is advertised at £X to £Y and they then offer you £X - N).