That could be...

The trouble with blockchain technology is the downside of its power: blockchain nodes converge on a consistent database, not a truthful database. It works great when there are several or more nodes eye the same process and audit (confirm) each others' data. That's how you get a distributed ledger that's censorship-resistant.

But what if the underlying data are hard to standardize?

This is where economics enter the picture. Redundancy is the price of censorship-resistance. Nodes, to properly audit new data, have to be completely independent-"minded" else you get self-reference errors. Convergence on a generally-accepted falsehood, if you will.

A lot of fake news goes viral because it sucks us into believing something we find plausible or want to believe: it preys on our confirmation bias. Moreover, it goes viral because it appeals to the shared confirmation bias of a tribe. That's where the self-reference errors creep in: the wisdom of crowds breaks down when other's assessments are treated as valid "data."

For news, the inputs for a blockchain solution - the "nodes," if you will - essentially have to be independent-minded reporters or reporter-bots. That would work for matters of fact, but the typical news item is anecdotal in nature rather than a raw datum.

It's going to be a challenge, that's for sure!