I quite like the metaphor, but the author doesn't know how "debt-to-income" (DTI) is calculated. They insist that DTI is a silly concept and instead propose "in

I quite like the metaphor, but the author doesn't know how "debt-to-income" (DTI) is calculated. They insist that DTI is a silly concept and instead propose "interest-expense-to-income ratio." They are under the impression that DTI = total principle / income. This is false. DTI is total debt servicing cost per unit time / income per unit time. The numerator and denominator do not have mismatched units, like the author claims. What's more, the author's proposed replacement measure--an interest-expense-to-income ratio--is quite silly. By only considering interest expense rather than the total cost to service debts, the measure becomes worthless as a means of estimating the capacity to take on additional debt. If you were to have debts that, despite being interest-free, were large enough for payments toward principle alone to completely consume your income, then you have zero capacity to take on additional debt. The author also proposed that a bank/lender is to a borrower managing financial debt what a CEO is to an engineering team managing technical debt. They say it without conviction, admittedly, but it is another quite absurd notion. Per the author's metaphor, a lender is incentivized to maximize interest income over the lifetime of a given debt (ignoring rising-rate environments); put differently, prepayment is to a lender's detriment. CEOs very much benefit from prepayment of technical debt. It's a very poor comparison.