The wall is not the code. The code is merely visible stone. By coordination structure, I mean the tacit, undocumented logic by which people, routines, judgment calls, and local exceptions actually get work done.

The founder could ship a function and then discover the next constraint from live use. The bank would have to ship a committee before it shipped the function, because in a bank the committee is not overhead. It is where many buried promises still have legal names.

Once I had that word, the incumbent choice stopped looking like a single strategy problem. I could see three rational moves. You can patch the fortress and learn where AI is genuinely useful. You can selectively rebuild rooms whose shape was dictated by scarce expert labor. Or you can grow something outside the wall, fund it, buy it, or at least study it before the parent institution teaches it to speak in meeting minutes.

This is why software moved first. Not because programmers are braver or cleaner people, though some will happily imply both, but because code is unusually checkable. Tests fail. Builds fail. Pull requests leave tracks.

Selective Rebuilders start from an uglier suspicion: some functions are human-scarcity artifacts. By a human-scarcity artifact, I mean a business activity whose shape was determined less by the business need than by the old price of skilled people doing the work.

So the incumbent question is not whether to use AI. That question is already stale. The question is which rooms should be patched for learning, which should be rebuilt because they were designed around scarce expertise, and which future rooms should be seeded beyond the wall before the main building teaches them old manners.