One important point is missing from this: building a cheap and good engine is not enough, there are more companies and industries that can do this than it seems

One important point is missing from this: building a cheap and good engine is not enough, there are more companies and industries that can do this than it seems. But you also need the maintenance and logistics network, with a ton of professionals trained for your engine type in particular. And for that you need to penetrate the market that is already captured. This is what stopping the most.