What you built over twenty years
Intuition about how long things take. What is hard. Where the risks hide. That intuition is your competitive asset. It is also becoming a liability.
When the paradigm shifts, expertise in the old paradigm does not transfer cleanly. The CTO who knows exactly why a six-week sprint cycle made sense may be the last person to understand why it no longer has to.
The update mechanism
You cannot update twenty-year intuition by reading. You update it by doing. This is not a metaphor. It is a literal operational requirement.
What building teaches you
Context is everything. The same agent with different context produces wildly different results. Until you have felt it, you do not understand it.
The work changes shape. You stop writing code and start curating knowledge. You stop debugging syntax and start debugging specifications.
Your measurement systems are wrong. Everything you are measuring was designed for a world where human cognition was the bottleneck. That is no longer the world you are in.