If you are interested in making an indie game, do it only because you want to not because you think you'll make money. You will lose money. That's it. There's no magic message here. Source: an indie dev. I keep my passion for my project because it's something I truly want to do.
And the fact is many people find making a game so intensely enjoyable that the net cost of making it is zero and they do it even when they're making no money or stand to lose money in expectation. Of course, there's huge variance in both directions, for every ten thousand indie game devs there's one Notch! And in reality I'm guessing being an indie game dev is at least slightly profitable in expectation. But the joy of doing it seems to drive their wages down to basically subsistence level.