again, not everyone is good with calculation and bitcoin difficulty, if you tell them they are going to earn blablabla bitcoin they will believe...
right. Personaly, I think 3 things came into account:
- there is hype and stories, and miners are scarce. If they are scarce, in people minds it means that there is something to get.
- the math are hard to get. Sorry but explain how works a decrease in value overtime is not linear but exponential :-), some people don't catch it really. I had to take 10 minutes to explain that to a colleague.
- and when you type "bitcoin calculator" on google, you arrived for example on a BFL sponsored page that fools you (
http://www.bitcoinx.com/profit/): sure there is a profitability decline per year on their calculator, but check the value. If (for example) you enter the price of the cointerra and its hashate, the site let you imagine you will make a profit.
Personaly until I used the "expert mode" with
http://www.coinish.com/calc/ I didn't know where to get a good simple calculator.
So people are guided on wrong information and (a bit) greed and hype.
Except your premise is wrong, same mistake as the OP. You are assuming difficulty will increase by something like 30% perpetually, which simply is false and impossible. The increase in difficulty will also slow down exponentially. We will probably NEVER see a 30% increase again. We are seeing mostly 20% increases nowadays, and soon even 20% will be history. So your "expert mode" calculator will also paint the wrong picture for you, because it assumes difficulty increase perpetually, which is simply UNTRUE, we've had many many difficulty DECREASES in the history of Bitcoin. We will probably see this phenomenon again within 6 months or so (as long as the price stays at $500 level).