Well, how DO you live off Bitcoin, even if you had an amount of coins if there are no interests to be earned? At one point, all your bitcoins are spent unless the price really shoots up to insane highs. Not everyone is able to start a bitcoin business or has a viable business idea, or the programming skills to do so. Seems to be that investing with bitcoin is incredibly hard to do since you cannot just send the coins to someone you trust on the internet just hoping she/he will pay you back with interest.