Back in the late 1980's one of my coworkers at a turbine component mfg plant in DFW, quit to go work in Olney, TX. Leland Snow, the founder of Air Tractor was tired of paying "Ferrari prices" for the turbine engines he was using in "pick up trucks". So Leland was going to built his own turboprop engine. Unlike a PT6, it was going to be a large diameter, high torque turbine (like the radial engines the turbines replaced), because a plane that maxs out at 130 mph doesn't need small diameter, aerodynamic motor.
Seeing the potential of the whole ag market going away, Pratt Canada started kissing Leland's butt at that point and built specific motors geared for the crop duster, with significantly lower cost. Now PT6 turboprops are pretty much std on all ag planes.
It wasn't until after Leland's death that Air Tractor made the L3 deal. Leland liked to make money but he wasn't about screwing people. Corporations like L3 don't care who it screws, as long as the shareholders are happy and they stay out of the press,