Homeworld's fleet manufacturing and deep-space exploration

How useful or realistic are Homeworld's logistics, research and manufacturing capabilities, which let fleets build ships from locally available materials?

The concept is considered useful and probably realistic for deep-space exploration, but the fleet needs the ability to process asteroids.

Homeworld's fictional fleets can manufacture ships from materials found during their journeys. That concept is considered useful and probably realistic for deep-space exploration, provided the fleet can process asteroids.