Thoughts on the fact that some very early adopters have 1000s if not 100s of 1000s of coins, which they obtained for next to nothing?
If they can sell a significant amount of their coins for anywhere near the current price, they are already fabulously wealthy, regardless of whether bitcoin is successful long term or not.
These people would have every motivation to ensure the price stays at a certain level by:
1. Investing in or creating bitcoin companies to make it appear progress is being made to developing market/ecosystem;
2. Promoting general awareness of bitcoin to the public - including participating in bubble creation and resulting media coverage;
3. Purchasing limit quantities of bitcoin at key times to keep the price moving in the direction they like;
4. Etc., etc.
See for example this article, especially the last 2 paragraphs: "The Scheme" and "The Moral":
http://rationalwiki.org/wiki/BitcoinThoughts?