I always wonder if it wouldn’t be something under NASA’s job to ensure compatibility between systems and components from various different rockets so that a Boeing could be launched from a SpaceX rocket and vice-versa or a Boeing fairing could be integrated on any rocket of the same class.

This would imply some standardised rocket stage widths, connections for fluids and electronics, as well as software standard APIs.

The result would be industrial opportunities for companies that can’t get the vertical integration of Boeing, Blue Origin, ULA, and SpaceX, but that could produce compatible components for assembling missions the vertical companies don’t want to pursue.