the problem with perpetual debt, you say, is that the federal reserve gets more and more power.
firstly the supply of money allows the exchange of goods and services so everyone can be productive, if those people are less productive than their debts, then they can't pay back what they owe, but the fed wants to keep money in circulation, and also wants to limit the moeny in circulation to limit inflation.(which should be kept at a helath low, preferably lower than the growth rate)
now the US dollar has for years been able to avoid inflation by being considered reliable by other nations, those who did not fear the US government was unstable and could therefore back their own currency with US dollars. So US citizens could buy with dollars foreign goods/services, and the foreign countries would exchange the dollars for their own currency.(especially lots of oil) This has increased the demand for the US dollar. (because the US has been considered the most stable and powerful nation on earth for a few decades, although the EU is fast catching up, and China will soon also be considered a super-power.)
Perpetual debt means that the is perpetually money in circulation, and that the fed is constantly making real profits for all the money the banks are paying it.(money which they likely just lend back out to other institutions if there is demand as there always has been)
but if people are producing more goods and services(being more productive) in your apples example, growing more food and producing more goods of all kinds (wool, milk, eggs, meat, leather, beer, and whatever else you can make from agriculture, maybe methane fuel) then they are all better off, irrelivant of how many apples they owe this one farm.
This requires the population to produce more than they owe in interest. Those who are not will lose out, and fall into poverty.