It sure is hard to continue mining @ ~ USD7/btc and I totally understand the OP's feelings. I'm still mining at this point; but I don't think it'll be profitable at any point in time. Whatever your reasons are for getting btc (usd, trade, etc), I don't see it going anywhere. I'm still mining because I hope I'm wrong. HOPE ...
BTC/USD prices has been going down since the $30 high. Those early adopters that sold at $30 have profitted and left the game, probably. Or they are playing with the market with the enormous amount of btc. Bringing the price down with the over-supply, make people leave, then bring the price back up for a profit. Who knows?
it's looking for a resistance, the price went up too fast, the growth of community very quick... now we need to see how many people stays and how many people leave! Consistency will pay back and what this community be challenge is the TRUST factor
Trade - It's just not enough businesses that know, not to mention adopted btc as payment. I recently had an experience with a handyman (got some work done to my house); to me, he's a very technical person for a handyman. He's got an Iphone and responds to his emails pretty frequently. He's well represented in the web (his own website, etc), and got his rankings taken care in multiple sites. And he accepts checks, credit cards, cash, gold and silver. He is the kind of person that I though would know about btc (because of his acceptance of gold and silver). But he has never even heard of it when I spoke to him about it.
it will take almost 5 years before BTC become of public domain. BTC still too technical!
there is only of 6MLN BTC of 21MLN think about there is not enough currency yet to cover a potential market... too much greed, not enough market to be spend it and not too many other currency accept it! BTC will be perfect to exchange between other currency like USD-BTC-EUR... BTW GOLD is up to $100 right now! It could be BTC instead gold in the future! Banks in the international exchange have the own currency to facilitate the transaction and don't lose the value!
The beauty of all of this if people leave the difficulty factor will adjust, it will be more easy to earn them as mining and thinks keep moving. Mean also when some one have a lot of them eventually will be as situation where will have BTC speculate for good purpose like create service exchange, goods and not necessary for greed