I agree compensation is probably the hardest hurdle to overcome.
I often try to figure out why my facitlity can pay agency nurses at the rates that they get knowing from experience what the rate difference is as an example prior to recieving my RN I worked for an agency as an LPN I worked at the same facility almost exclusively that I have now gone to staff in as an LPN agency I made three dollars an hour more than when I started as a staff RN.
I feel that most agency nurses are working agency because of the money. I know it was my motivator when I did it. So my thinking is that if a facility raised it's starting level rate of pay to within a reasonable difference of agency pay then offered benefits and chance of retirement, and annual raises and bonuses, then most or all of the nurses working agency would come on staff. Noted that of course all pay rates would have to include current employees and at the time of the new rate all employees will start over and begin their annual reviews and pay raise of 3-5% depending on performance.