Anyone can call it ponzi scheme and fraud but if you think of it, everything worldly is fraud. You buy apple products with thousands of dollars but how much are they really worth? Why would people give out thousands of dollars for a macbook when they can buy a laptop for $300? Is it really worth that much or is it just another ponzi scheme that apple is bringing to the world better gadgets than any other brands? So we're talking about bitcoin now. What are we really paying for when we buy bitcoin? We pay for an online program and the people running the program helping transactions go through, or we call mining. Miners put in so much time and most especially the cost of mining is so much. That is merely the reason why bitcoin will cost much and if incase it will dive too low and will not be enough to pay for miners, then that could be the time bitcoin will die, or not.
They will always say that apple is backed up by a physical product, regardless of its true value. You gotta remember that what gives bitcoin its value is trust, not a physical thing, and that's hard to grasp for many people, specially since so many have been screwed before in ponzi schemes (lack of trust on their side), I'd say bitcoin is a long way away from dying from personal experience, and if the price is too low to pay for miners is because there are too many miners at any given time (look at china operations), at least that's what I think.