Some manufacturers have a monopoly in a certain class of engine thanks to type certification. The certification and liability that comes with it are prohibitive

Some manufacturers have a monopoly in a certain class of engine thanks to type certification. The certification and liability that comes with it are prohibitively expensive for new comers. The PT-6 is an example of this; in North America, it stands alone, undisputed king of it's class. What's ridiculous is that turbine engines are simple. More simple than piston engines, and everyone and their dog can build a piston engine.