So the cost of mining compared to the value of bitcoin can not be ignored, it is a huge aspect of will bitcoin die, or is bitcoin dead.
I agree that it can't be ignored in general, but not in the context you describe. If a coin was a one time thing, like a token of computational power, a work unit, then you would be right. But that's not the case. When you create the metaphorical coin, you create a thing that will persist forever. Its usefulness in the long term is what gives it value. This relates to the inclination of people and businesses to accept Bitcoin, inclination to "hoard" coins, sentiment of the potential users, etc.
Why some people think like you do, is because they don't actually make use of Bitcoin at all. If your only involvement is mining coins and selling them, of course you will see it as a computational work unit. But please keep in mind that it's not even tangential to what Bitcoin is all about.
If it cost more to create a bitcoin then it does to buy something with a dollar vs a bitcoin then bitcoin is not working and will not work.
Why? Just stop creating them if it's not working for you. What's not working is creating them at that cost, not the Bitcoin system in general.
If you do not mine and you just buy bitcoins, then I guess you can take the mining aspect out of it, but at that point your still buying a bitcoin at 6 bux one month and next month its at 4 bux or less, how does that system make sense, it doesnt, so it needs to correlate with the cost of mining and has to have some type of stability in the 10 to 15 per coin area for everything to work together and for it to all make sense.
This is the issue about volatility, and I agree that this may be a problem for some, and will be over when we have more speculators in the market, which might take a few years at least. Otherwise, your numbers are arbitrary. You are saying that when the exchange value to dollars are falling, it doesn't make sense to buy? Hell yes. But how do we know what the prices will be at any point in the future? Again, while I agree with the sentiment, an options system can limit the risk, so there is a solution to that waiting to be implemented.
Plus, price does not, and cannot correlate with the cost of mining (although there may be some feedback as thejoint puts it), cost of mining comes to terms with the price, that's the mechanism in place. The difficulty is decreasing, and your 10 to 15 per coin will be less and less, until (if ever) the exchange value increases. So again, those numbers are temporary.
Miners who whine need to quit mining. That's practical reality. I always recommend people not to get into mining in the first place. Hand down mining to professional businesses. Buy shares from mining companies instead, if you really want to invest in that..