Actually, what is almost guaranteed to happen is either (1) Bitcoin fails completely and drops to $0, or (2) Bitcoin continues succeeds and naturally continues to appreciate in value to $100, $1000, and more. The chance that the exchange rate remains stagnant, say between $5-50, in the next decade (we are talking long term investment here) is almost zero. Mark my words, it will be either scenario (1) or (2).
It's basic math. If Bitcoin succeeds, and if its economy grows by 10x, 100x, etc, then its exchange rate should increase by 10x, 100x, etc, because there is a predetermined finite number of coins. (Except that we have mined only half the coins up to this day, but you get my point). The question is how quickly will Bitcoin succeeds? Will it significantly rise in value over 0.5 years, 1 year, 3 years, or more?
You mean to tell me that in the next 10 years, either Bitcoin will fail, or it won't? Your level of perception is amazing! Everyone involved in Bitcoin knows that.
What we don't know is what the value will be one year from now. Two years ago, the price was less than $1. Then it rose to $30+, and fell back to $2. One year ago, the price was less than $5, and it's been a slow steady increase over months to what it is today. The question is, what's the price going to be in one year? We don't know.
I think we will be above 100 million by next summer. Your numbers under these assumptions are solid and I like the website for calculations as well. I think we will be around 50,000,000 by July and that is the earliest that someone could get there rigs from BFL.
Right, so someone places an order today, they get them in July with a difficulty of 50M. Lets say by the end of the year, the network is up to 150M difficulty. You're still talking at a 100% ROI of less than 6 months.
The end result would be: What option makes the most amount of money in a 1 year period of time.
1) If you buy BTC, you're looking at throwing 4,000 BTC in a wallet, and letting it sit there.
2) You buy from BFL, sit for 6 months, and earn 4,000BTC over the next 6 months after that (when you start mining).
Both options end up with the same result: your ultimate profitability is bound by the exhange rate. However, one option gives you hardware you can now resell, or keep mining for another year, and make even more BTC.