Not in commercial jet engines. The four big players have been in the engine game since the 1920s-1940s. Others came and went, some were bought or merged into them, but no one has eaten their lunch.

If they were still using the same designs they made 50+ years ago (like the rocket industry in the 2000s) I would agree with you... but they aren't. They have been constantly pushing performance to get better thrust-to-weight, efficiency, noise, etc. Whenever they get lazy (which they have) one of the other players is the one that gets to dine well. Look up "The Airforce and the Great Engine War" for an example.