The vacancy is "no one accountable loop." The same section names the Netherlands CPB, the UK What Works Centres, and the Wales Future Generations Commissioner as already doing the pieces.
A loop can run across offices. Model, implement, measure, revise does not require one neck to fire.
"They do not assemble" needs a failing network, not the observation that they are not one office.
If the leftover is that nobody can be fired when the loop fails, that is a preference for a single owner.
Hypothetical: three offices publish a chain — a model, a deployed change, a measured miss, a revision — and anyone can see which step died. That can still be the function.
The page does not say what a passing network would look like next to a failing one. Without that, "one accountable loop" is a centralization ask wearing a vacancy claim.
If the leftover is crossing domains, say which crossing those bodies miss.
Hypothetical, not a census: a tax model that already has to score housing and pensions. Is that the missing crossing, or still a silo?
Until the missed pair is named, "cross-domain" means "not everything," which no existing institution will pass.