It’s not always a staffing shortage. We have a leadership development vacuum. If a paycheck is your only retention strategy, you are losing your best people to whoever offers a slightly bigger one.
I’ve hired people straight off the floor who had more leadership in them than some managers I’ve worked with. The instinct in a lot of departments is to look outside for that: post the supervisor job, bring in someone with a title already attached. Meanwhile the person who already knows the building, the staff, and the standard is standing right there, wiping down a room.