I was a little bit quick there..You're right about the first part I think. But if price drops difficulty is adjusted down and unprofitable miners will quit. I don't think it always will be profitable to mine? Depends?
So if I'm not mistaken - if Bitcoin went down to $1, even my Macbook could possibly be profitable to mine on? And if interest in Bitcoin disseapears completely, no miners has any incentive to mine and there would be no more transactions, and BTC is dead.
But this is highly unlikely because of the state things are in, and all the people involved.
Yeah, that's about right. If Bitcoin dropped to $1 then your Macbook be able to mine many bitcoins, but the profitability would be similar to today's, as these many bitcoins wouldn't be worth much. If interest in Bitcoin disappears completely then yeah - no transactions and The End. There could however still be some BTC enthusiasts to maintain the system (keep miners on standby) allowing for any transaction to come. I find it hard to imagine that the interest disappears completely, as with dropping price, the transaction cost would also drop making it more attractive. Anyway, bitcoin is design to attract miners (secure transactions) at any price, but I could also imagine that the higher the price, the more secure the transaction network is.