And also of engines - one of the reasons relatively small companies like SpaceX and Blue Origin can design their own high-performance rocket engines is that the

And also of engines - one of the reasons relatively small companies like SpaceX and Blue Origin can design their own high-performance rocket engines is that they can simulate combustion and fluid flow using CFD techniques. Back in the F1 days they had to light up the engine and come up with interesting ways to observe the internal processes and debug instabilities; now many of those debug cycles (and associated manufactured test articles) are unnecessary. You still have to build the thing to catch some bugs, but that's gotten much cheaper.