One thing that I did not appreciate as much before reading this book is to what extent engine design is driving the timeline of the development of a new aircraft.

The situation is a bit similar to SoCs, if you have a Snapdragon chip with specific characteristics, that defines what kind of smartphone you can build around it.

If you want a new disruptive airplane/smartphone, the engineering of the engine/SoC will be what will be driving your product timeline.

Airbus A300 early studies started around engines that were already manufactured for other aircrafts because Rolls-Royce and the UK government made the wrong bet to think that the RB211 project for Lockheed was going to be more successful than Airbus and cancelled the RB207 project.