From my few decades in the engine business, I can state that those engineers who aren't competent and dedicated and creative, and learning more every day, do not last long in the design business.
The ones who are merely marginal (but good communicators) might wind up in field service, where they have to live in the real world of engine operations. They then can convey that experience back to product improvements and newer generations of engines. (I'm not impugning all those in field service - most are first class and love their work.)
But the ones lacking in integrity or talent get recycled as shoe salesmen.