Because hardly anyone knows about bitcoin today. If that isnt going to change, a price drop to $1 or less is completely logical. The speculation was that bitcoin would gain more widespread use, it still hasnt happened. You rightly say miners joined this summer, expecting to make a killing by just running their computers, that bubble has burst. What will or wont drive longterm bitcoin price is its acceptance as a currency, something which hasnt progressed a lot since last year. Thats far more important than short term speculation which is driving prices currently.