I often try to explain to family and friends that it is mathematically impossible for everyone to pay back all their bank loans, since ($Money_Created + $Interest) will always be greater than $Money_Created.
You should stop trying because you are wrong. It doesn't matter than MONEY + INTEREST > MONEY. As long as the value of all the assets is greater than the value of all the debts, then all debts can be repaid.
You are the one who is wrong.
the debt is denominated in fiat.
you can't repay a 10,000 USD loan with barrels of oil, you have to trade the oil for USD first in order to pay the debt.
hence because all fiat in existence is less than all debt in existence (because of the interest) and new fiat is only created by loaning it out and hence creating even more debt, the total debt can never be repaid.
not only that but if people don't take on more debt fast enough the debt grows faster than the fiat supply and eventually someone has to default on their debt.
you are right!
defaults are the only way we can keep our system alive because they actually destroy "invented" money including the interest.