This title is completely wrong. The article estimates the US has accumulated around $2 trillion in war debt as of 2020. It goes on to estimate interest payments will equal $2 trillion by 2030 and $6.4 trillion by 2050.
Anyway I didn't say and didn't mean it's the only valid interpretation of 'spent', just that it is one.
You might in a state of nature, but the US has laws against prepayment penalties for mortgages. (Well, against the mortgage originator charging prepayment penalties.) You don't owe interest until it accrues.
Yes, you will. "accrued interest" is "unpaid interest as of the time of ___"; at the moment you sell the house you will have paid all of the interest up to that moment.
There's no early-payment penalty on mortgages, as of the last many decades; maybe that's what you mean?
"20 Year old slow-burn war available for reasonable price. Population w/ low morale, lots of growth potential! Motivated buyers only please."
I'm hopeful, though not at all optimistic in the short term, that it will now be EOL'ed. Unfortunately, as a product class these things tend to be very durable, and families can pass them down for generations as a curiosity until someone decides to put it back in the market. Or some new startup sees a chance to innovate while moving fast and breaking things.
However, since there's an open market for t bills, the treasury could buy back a certain number of bonds that people are willing to sell.
However it's not quite the same. The only reason that problem don't calculate the cost of the mortgage over time is that they are more concerned with asset values, not because it's better accounting.
Among various things that could happen: I might pay off the $400K next year and pay a grand total of $411K in interest. I might sell the house for $700K and book a $200K profit on my $100K cash. I might lose my job, get foreclosed upon, and then be out $100K plus whatever payments I've already made. I might have had $500K in cash to begin with, but wanted to invest $400K in Ethereum, see it moon for a 20x return, and make a cool $8M profit on top of the house. Or I could carry the mortgage to term, and then I really will have spent $700K.
So because we spent bonds instead of spending dollars, we can not take their dollar value as the cost, because that's most definitely not what we printed for these.
I do appreciate the details though, as it does help people understand the way that we have set up these institutions, which in turn points to what we might want to change to make the process better.