IIRC their development cycle for a ground up design is about 30 years.
> Boeing agreed to deliver the first 747 to Pan Am by the end of 1969. The delivery date left 28 months to design the aircraft, which was two-thirds of the normal time.
surely they can do a ground up design in under 5 years?
It is legitimately very difficult to make a plane as cheap and efficient as airlines want, and as safe and (relatively) quiet as regulators want. Boeing and Airbus are not a duopoly because of a lack of attempts. And even they screw up; the 747-8 and A380 turned out to be duds because they were too hard to fill and four engines needs more fuel than two.