Mathematically, we are assuming that the changes are sufficiently small that we can linearize
the budget about the equilibrium state (as we did explicitly in our previous analysis of the zero - dimensional EBM).
Unfortunately, these estimates reflect profit margins that remain
about 70 % above historical norms, and are primarily driven by unusually large
budget deficits and depressed private savings (the deficit of one sector must be the surplus of another in
equilibrium — see Too Little to Lock In for the accounting relationships here).