You can't say one thing, argue the completely different side, and then refuse to understand what I am trying to say one bit. I am not sure who made the rule that you are not allowed to calculate speculation into mining but it is wrong. Any bitcoin miner immediately becomes a speculator the second they help solve a block. You can be safe and immediately sell it, or you can take a risk and speculate. If you speculate on coins that you mined yourself you are making a profit off of mining because you mined the coins that you are speculating with. If I just bought the coins I would be speculating, but because I mined them I am allowed to combine the profit. There is no logical argument against that as far as I am aware.
Then to follow your approach by combining the apples and pears:
The amount of profit you accumulate overall by speculation and mining will be - in case of rising Bitcoin prices - always lower then the possible profit made by pure speculation without any mining. So your maximal profit that you can achieve with a given amount of money will be diminished by mining, leading to the conclusion that mining generates a loss.
Have you ever even owned a usbminer? I feel like most of the people on this thread are talking but they have absolutely no evidence to back up their claims. Let me make this very clear: I am not endorsing usbmining I am just saying that they will one day in the very distant future make a profit. I do not and will not ever buy more than one of these purely for the sake of experimentation because they are interesting devices and if the technology was perfected they could one day become a viable source of income.
Yes, I traded a MMOG-Account with a friend for his USB-Miners. He was eager to get rid of them, I didn't play anymore, so it was a quite reasonable trade.
(Ah, but to follow my argumentations: Of course I made a huge loss in this trade. Because I have to calculate the money that I could have gained by selling this account for money, then buy Bitcoins with this money. That would be the 100% that I could have made by selling this account. By trading it for USB-Miners I lost roughly 70%-80% of this value. This already includes an assumed scam-rate of 20% during the selling process of online-gaming-accounts.)
OKAY I will meet up halfway with you because I am a good guy, let's use your side of the argument that mining generates a negative profit. Even if it takes years to do, if the usbminer somehow magically mines .00000000000000001 more btc than it took to buy the thing(not counting speculation, we will assume price never increases but difficulty does) a profit has been achieved, do you agree? And you can't just say "No that will never happen" because you don't know for sure so please don't go there. You will not make as much as just flat out buying the btc, and definitely not as much as a legit rig, but if it one day makes more than it cost to buy you get a profit purely from mining. My arguement is that this is possible. Slow, but possible.
You are saying that a usbminer will never reach the initial investment that it cost to buy purely from mining btc and selling them immediately? Correct? Just try to see my point because we aren't being productive anymore we are just going in circles.
If the miner generates more bitcoins than it took to buy, it generated a positive profit. But it won't.
By using the numbers of the mining-speed-delivery-thread in this forum, my calculations show that the current Hardware won't make even half the amount of Bitcoins that it takes to buy those things. Even if i assume a complete stagnation after the delivery of the current preordered Hashrate, it wont return the investment in a 20 year timeframe. After that I stopped calculations.
It takes several - and at this point in time very unlikely - assumptions to get to a positive ROI. And those have to factored into your profitability-calculations as a risk-factor.
The other problem in your logic is still, that you assume the hardware investment as only parameter in calculating the overall profit. To say your miner generated more money including speculation than it's initial cost in Dollar is profit - is flawed. It only works if the Bitcoin prices are rising. And when the Bitcoin prices are rising, the maximum amount of profit you can make is by buying Bitcoins without mining. Again,
this value is 100%. Everything less is a loss, because you did not get as much money as you could have gained.