[masklinn]

One of the big issues wrt "major development projects" is that engine manufacturers are working on pretty interesting concepts but it's not clear if they'll pan out, and that means if you lock in a program too early you might completely miss out on this new generation of engines and end up with a plane missing the market.

I don't think Airbus wants a repeat of the A380.

Plus last I'd checked Boeing declared they're not working on a new frame for at least a decade, and Airbus is competitive right now, so the incentive is limited: Comac is up and coming, but it's still a way away (and is missing the entire support network).