I think I recall hearing that some companies like Overstock.com were actually keeping and not selling at least some of the bitcoin they got from sales.  I think the biggest detriment to btc value is the inherent fear and uncertainty caused by the crooks who do various crimes rather it be Mt Gox or just hacking a weak password.  There are failures on multiple levels and the responsibility is on the shoulders of users, website managers, business owners, bitcoin devs, etc.  But really, if bitcoin were really secure from inception then we wouldn't have any of these problems.  Maybe some other currency that is user friendly and secure will supplant bitcoin.  It's really not that far fetched even though bitcoin has it's followers it also has pretty severe flaws.