You know this, but many users of AOL didn't. To them, AOL was equal to the internet, like many people believe that cryptocurrency is the only application of blockchains as a data structure.

> Cryptocurrency is a vital component of the distributed blockchain architecture.

It is now, but that doesn't necessarily have to be the case. Cryptocurrency is one of many applications that can be built on top of a distributed ledger. There are many applications that have nothing to do with payment processing.

I disagree with the notion that a cryptocurrency is a vital property of the distributed nature of blockchains. The purpose they serve now is to incentivize individuals to participate in the network who wouldn't otherwise participate by paying them a currency to represent the value of the service they've provided.

But for instance, you could also have private blockchains where the incentive for running a node is access to that blockchain's data. There does have to be an incentive to run nodes, but it doesn't necessarily have to be monetary.

That's not a decentralized blockchain. It's the decentralized consensus that is novel. Without decentralization, it's just an append only database.

As for compensation, rather than receiving a coin as a reward for doing proof of work mining, you would gain a key to enable you to read certain encrypted data on the blockchain, for instance.

And your scheme does require some amount of trust. Induction into the consensus node set would need to be controlled to prevent bad actors from disrupting the flow.