Every debt is a promise by someone to dig resources out of the ground or grow something or exploit someone in the future, plus interest. Government debt is a promise to tax those promises, and a tax rate of 25% means the government has to encourage 4 times its debt in future GDP (yes, disaster spending counts, too) in order to cover the debts it creates (and that debt increases when it cuts taxes to encourage private GDP on the Invisible Hand Job premise). Whether inflation allows printed money to pay old debts on the cheap or not, the same amount of resources will be required, just more money gets shoveled around to do the same work. At some point, certain resources are depleted or become too expensive to obtain them or prevent system failure(social stability, maintenance, law enforcement, climate stability, land contamination, infrastructure decay). There are nearly infinite places that we can get blindsided by complexity, as well. The more technologically advanced our systems get, the less aware people become about how complex that technology really is. Sooner or later, the systems have to either fail or eat us. We built them to compete for dominance, after all.