"...could be implemented and managed..."

That they could. Anything could. The question I don't have a convincing answer to is why would they use the Blockchain?

There's a very simplistic "in principle" reason to consider the blockchain. It can store information symmetrically - i.e. once you have access to it you have complete ability to search it and reuse the data, and it can't be "lost" like data you've stored on a server or a hard drive - it only goes down if the whole network does. This maximizes information availability and reduces the middleman problem to "who provides hardware and bandwidth" and "what ui is available for accessing the blockchain."

Although bitcoin makes the blockchain look capitalist, its underlying tendencies are like that of the internet at large - self organizing infrastructure for information.

I think the general idea is, why should we put trust in one entity/person, when we could distribute the "trust" to all users.

I think we can agree that distributed is better for the consumer than centralized (privacy and availability), but given that the Blockchain is not the only way to achieve a distributed architecture, I'm interested in why I would use the Blockchain when I can achieve similar results with an arguably simpler solution.

It's the only decentralized system that can guarantee availability. Data stored in Freenet, BitTorrent and the rest is ephemeral.

The Blockchain is a ledger, BitTorrent is a peer-to-peer file share service. Difficult comparison.

What other systems exist that provide distributed trust architecture?

Blockchains allow people to enter into agreements that don't require enforcement. They're enforced by the programs that generate and validate the blockchain. Eliminating the need to enforce agreements will make them easier to enter into. Blockchains make it easier for people to work together.

The problem with this statement is that for it to be true, everything referenced in the agreement has to exist in the blockchain. The system can't seize collateral that is real property. That still needs to be enforced by the courts and the sheriff. Whoever finds the way to match borrowers and lenders using bitcoin but with traditional collateral enforcement is going to make a lot of money.

A cheaper version of western Union is great and so is reduced fees for merchants. There is so much more that can be done with blockchain technology but I don't think it well happen as soon as 2015 because of the chasm between the people who understand the technology and the people who understand the business and law.