First of all I would like to start this off by stating that I am a believer in the possibility of the success of Bitcoin. This may seem like a contradiction with the title of the thread but it is not. This is because the possibility of success is very low due to the reasons which I am going to describe. At the moment bitcoin is 250$ and has been there for quite a while. Exchanges such as cryptsy, poloniex, btc-e, ect. exist to exchange btc to usd and btc to other alt coins. Circle and coinbase exchange btc to usd and are currently common way to receive USD from BTC. That is a brief summary of the current ecosystem.

Now let us imagine that bitcoin reaches "the moon" as is often wished for in the Bitcoin community. Let us imagine that one BTC is worth 1 million dollars. It is commonly accepted that these exchanges, cryptsy, poloniex, btc-e, circle, coinbase, ect. are for profit. They are not running their businesses out of altruism, but for profit. If one bitcoin is worth one million dollars, how is it remotely imaginable that these exchanges will not just run off with the coins? Even more if I have one btc at one million dollars, I will have to go through some sort of intermediary to receive my USD. This intermediary will run off with the coin because of its massive value.

The issue is a facet of human nature, greed. One bitcoin would not even have to reach 1 million usd for the above scenario to become a reality. How high does btc have to go? The 1k mark was enough for mt gox, 2k...would there still be trust? Would they all run off with the BTC? Ok how about 40k?

This is the problem of bitcoin. People steal. Especially when it is irreversible.