That's not how that works, because for each unit of debt (loans or negative balances) there is a corresponding unit of credit (bonds or positive balances) in the economy. Hence, mathematically speaking, all debts could be paid off instantly at any point in time.

The reason why the debt keeps growing endlessly is that there is a 0% lower bound on the interest rate, which if you think logically about it, means that debt can only grow, mathematically speaking. This creates the impression that debt is always a future burden that is eternally carried forward as if it was nuclear waste.

If the market interest rate is below zero, either the government and the central bank must intervene to maintain the state of the money system above zero, because that is the only representable state. The government can subsidize the difference between the market interest rate and the money system interest rate clamp by taking on private debt and turning it private. This is particularly evident once private corporations refuse to take on further debt.

However, even if the government stopped the subsidization, you still don't get out of the conundrum. The government is patching the symptom with its cause, which stalls the problem into the future, which is "good" if the cause is considered good and only the symptom is considered bad.

The same way housing is needed for living, money is needed for trading. Similar to housing becoming an investment and therefore no longer being able to be used for its intended purpose, money can face the same fate. When people use money as an investment, it can't be used for trading. Houses sit empty and money sits idle.

It turns out that money is such an integral part of the economy that if there is no money, people can't acquire the goods they need to survive and since there is a monopoly on money systems, you can't just switch to a private provider to perform the trading you need in case the government one fails.

In other words, you either choose between a fully formalized money based economy or subsistence lifestyle with nothing in-between. The difference between the two is so stark, that a failure in the money system might as well be the collapse of all elements of society. From that perspective, it is quite smart to keep kicking the debt can down the road. Meanwhile the person who refuses to kick the can will doom society unless they implement the possibility of negative interest in their money system.

The zero bound on nominal interest rates is not relevant today. (It may be relevant in a deflationary environment where debt or 'safe assets' are essentially needed as a liquidity instrument akin to money, but that all gets hoovered up when interest rates rise.) The U.S. government is paying a whole lot of interest on its national debt bonds not because of a formal constraint, but rather because its bonds would go unsold otherwise, it would be unable to roll over the existing bonds as they expire, and the whole house of cards would collapse. IOW, it's the chickens coming home to roost, and the American taxpayer is paying for it. The alternative is to inflate the debt away by debasing the currency, which is even worse.