Then you'd need to explicitly mention your definition of "fragmentation" because i think mine's differ.

When i hear about fragmentation i think about incompatibilities, like -e.g.- the home computer fragmentation of the 80s or the Java ME fragmentation of the 2000s. However there are very few incompatibilities between modern Linux distributions and you can avoid them when you are releasing software.

Don’t you think this depends on the exact process followed? Different countries built the ISS after all. So long as you plan and standardize properly, and write to the spec, you can develop east subsystem independently and still integrate it as a single, cohesive system.