So then put up multiple job listings with different salaries. State what the skill expectations and senority requirements for each are.
That's impractical most of the time. It's much more efficient to handle leveling during the interview process, and to coach the technical recruiter to use screening questions that give a decent indication of where a viable candidate might slot.
It's also easiest for candidates. If you are faced with 2 job postings about the same org at a company you may not have any experience with, how will you decide whether to apply for the lower or higher level role? It's not always clear.