Nfl is the best run pro sports leauge by far and they use it. Players will sign where ever the money is, players who love the game and play well are rewarded, players like Mike James, Eddie Curry, Jerome James sign big contracts and destroy the ability of the team to be compeditive untill they are unloaded.
Players would get signing bonus so they would get security. And where will these players bolt too? The Eruo leauges will only pay so many players. The system now is broken on two levels, a team is screwed if they sign a guy and he doesnt work out, it may take years before they can contend and we are seeing lots of good players get max deals use up all the money from 29-30 teams then we start losing guys who want to stay but cant get paid so they go over seas.
As in any other job, perform get rewarded, dont show up get fired. Why souldnt it be this way in the pros?