He is obviously very gifted at analyzing companies and making good investment decisions based on the information he has available. Coca Cola, Goldman Sachs, etc. are his area of expertise. Blue chip stocks. Companies which have strong fundamentals.
Obviously Buffet made some very bad valuations. Most banks would have gone bankrupt, if the government did not bail them out. They made very bad business, selling shit as top notch investment (e.g. MBS) until it blew up, but got another free ride from the tax payer. Buffet made after the Lehman collapse an even bigger bet on that, without bailouts he would have gone bankrupt too.
http://blogs.reuters.com/rolfe-winkler/2009/08/04/buffetts-betrayal/Yes, Bitcoin's value has been largely driven by speculation and based on the real transactions being done on the system, its market cap is very high. This is the tech industry in a nutshell though. Companies trade at 100+ P/E ratio.
You can't compare a technology with a corporation. And bitcoin is not just a technology, but a revolution - that's why so many people don't understand it.
Well, if all the banks collapsed, then a lot of people in the United States would likely be bankrupt right now. Buffett is not accountable for the financial collapse simply because he is an investor. Most of the business practices of those companies were masked as low risk. Without insider information, it would be quite difficult to know how they were bundling those loans. The people bundling them didn't even understand them a lot of the time.
As for the Bitcoin being a technology as opposed to a corporation, sure I agree. But what we are talking about is the value of a Bitcoin here. This value is what the market is willing to pay for a Bitcoin at a given point in time. This value is based on something. Whether it is the future potential of the technology, its scarcity, or more realistically a combination of many factors, it is still based on something.
To say it's a revolution and it's going to replace fiat, I'd say that's retarded. Governments aren't going anywhere. So long as they are in power, they will encourage the use of their own currency. At the moment, Bitcoin is not a threat to the dollar. If that changes at some point, it will be a very easy fix for the government. Just do what China did. Outlaw using Bitcoin to purchase consumer goods.
Bitcoin needs to find a way to complement the USD and other currencies. It's not going to overthrow the financial system.