Second hand markets help to keep the primary market propped up higher than it otherwise would be. If you can buy something and it retains resale value, then the initial purchase price is more worth it. Whether that balances out with supply/demand and price/sales numbers if there were no resalability is another question.

It’s like saying everything is a wave IRL.

It’s a common misconception: whats happening is that -fr is dangerous and it doesnt want to preserve the root. So you need to use the flag to tell it “No, Preserve Root!”, hence you must use the --no-preserve-root flag just to be extra safe.