Developing systems, programs, and quality assurance all are all fairly different skill sets. A gross, possibly inaccurate simplification could be:
- systems is about thinking how different things fit together
- development is about building something
- quality assurance is about figuring out how to blow something something up
The thing is, I know technical people that I wouldn't trust to do one of the above, let alone all three at once. And I know people who can rock it in multiple disciplines. When it all comes down to it, focusing on the quality of the people you work with and helping them thrive is a solid plan.