Maybe I'm misinterpreting you, but I don't follow the reasoning behind "getting interest in BTC" is simply impossible.  For example, if I loan 0.5 BTC to someone who wants to use it to buy a car, would it be impossible (or even unreasonable) for that person to be able earn and pay me back 0.6 BTC over the course of 5 years?

Sure, there's always a risk that the borrower ends up defaulting; but that doesn't necessarily mean it was inherently a scam or irresponsible in any way from the start.