Couldn't Blockchain technologies along with big open source projects become a great source of big data? Ideally used with open-source projects. I'm thinking Augur for one but a lot of projects connected to the Ethereum network feels they could be great source of data that can be analyzed.

I agree right now big data centralisation is a problem indeed, but I don't believe it will last. I mean, those big companies will remain but Blockchain tech is fairly likely to take a big spot in there with them, I believe.