Developers add cleverness until only themselves grok the accidental complexity, QA and BA's develop the actually useful bits on the side, the developers quit to implement more Cloud at the next startup.
Introducing the Q shaped model...
T shapes are used also for building teams so you think about an overlap of people who understand at a high level what others are doing but still emphasize the individual specialization of subject matter experts. It's like Tetris but for teams.
“a T-shaped organization is both good at the management of its existing operations, as well as being good at the strategy and innovation needed for a healthy future.”
Some might say that this just describes a ‘viable’ organisation.
Being more practical about it, Gordon Moore’s Escape Velocity would be a good modern read.