If A(n)=1 (i.e., more attractive employers aren’t actually doing more useful work) then the Miller marginal-utility loss is 1/M(M+1) and the gjm marginal utility loss is 1/M-1/N, for much the same ratio as before.
If A(n) or B(n) or both decrease really quickly with n—A(n) = 2^-n, say—then the error is smaller.
The super-naive approach of pretending that the marginal utility loss equals the utility your work would have done is a much better approximation than “replace self with next-best candidate and change nothing else” is.
A few other remarks.
If A(n)=1 (i.e., more attractive employers aren’t actually doing more useful work) then the Miller marginal-utility loss is 1/M(M+1) and the gjm marginal utility loss is 1/M-1/N, for much the same ratio as before.
If A(n) or B(n) or both decrease really quickly with n—A(n) = 2^-n, say—then the error is smaller.
The super-naive approach of pretending that the marginal utility loss equals the utility your work would have done is a much better approximation than “replace self with next-best candidate and change nothing else” is.