I mean, the "right price" for a 15 year old 787 (with a fresh new set of life limited parts and maintenance checks) is around a third of the cost of a new one and they're now starting to be parted out for their components (newer 787s have updated GEnx engines with better fuel economy, which is a big part of their higher value). And Boeing reckoned they needed to sell 1100 units to break even on the programme, which is a lot aircraft to sell if your design is only competitive with 15 year old aircraft airlines are trying to get rid of. People are already starting to breaking up old 787s for scrap because there are more buyers for spares than old 787s...

China may or may not be much more than a decade behind in their engine technology, but there's no commercial case for designing a new aircraft with engine variants so outdated they wipe >$100m off the sticker price of the aircraft....