Those same Diesel engines are available from India and several other countries. Again, it's like the AK-47. Somebody really good got the design right, and now o

Those same Diesel engines are available from India and several other countries. Again, it's like the AK-47. Somebody really good got the design right, and now others can just replicate it. Diesel engine design is non-trivial. It takes a lot of compression to get the heat necessary for ignition. It takes strong structures to handle that pressure. The fuel injector has to be able to overcome the pressure of compression and spray fuel into the cylinder. You need to get more energy out than you spend on compression and injection. The thermodynamics are complicated. That all gets built into the dimensions of the metal parts, and it all looks simple, but it's not. Those little engines doesn't even need a glow plug to get started. Or even much cranking. They just work. Cheaply.