It's crypto, you can't understand it unless you already believe in it.
From the outside, blockchain looks like a spread sheet that's so difficult to edit, you have to turn it into a slot-machine to incentivize people to try. But I don't understand blockchain.
What data? Tor is designed in a way you don't have any useable data if you don't control a significant portion of the network. And even if they could control it, how much is that data worth anyways? ISPs don't get rich selling traffic data afaik. Blackmail maybe?