Pair and Mob programming practices are far more effective approaches to writing production software than individuals working alone.
The thing that slows delivery down the most is not the speed of creating new production code, but the fragmented distribution of understanding of the technical and business domains, in combination with how the code meets the needs/problem.
With collaborative methods of producing code, knowledge is combined, created and shared in context, resulting in
- Less work in progress and queues of half completed work
- Simpler, more effective solutions to problems.
- A huge percentage of bugs and defects never occur or are caught before immediately.
- The skill levels of the whole team are amplified and increased over time
These factors combine and compound, with the outcome that over time a team that is collaborating effectively will significantly outperform a group of people that is working in an isolated, divide-and-conquer approach.