United 777-200 fleet faces an uncertain future after Dulles engine failure

"...777 fleet faces an uncertain future after Dulles engine failure ... and also before Dulles engine failure, for reasons having nothing to do with the Dulles engine failure."

To be fair, I read all of it, and both sides of the question interest me. But the engine failure and the economics of the 777 are totally different things.

The article's TL;DR is that the economics of 30-year old P&W4090 engines make these airframes even less useful to United.