When we think about decentralization, we sometime think about uncontrolled extreme decentralization. That's the ideal : no single point of failure, with everyone hosting their data where they want, and deciding who access what about them. Practically, as pointed in the article, there are laws to comply with and those are IMHO the biggest lock to decentralization. The fair middle ground between extreme centralization…
Unfortunately, the world decided to go the centralised way. At some point I had to re-work my outstanding papers, because any mention of peer-to-peer or even decentralisation meant immediate rejection. Internet service providers went more greedy, so if you don't build your own global backbone to have some leverage, you need to pay someone who does or you're hosed. Even the laws in place start to strongly reflect an expectation of overpowered centralised platform beneath any communication.
Then, finally, what we ultimately need is to figure out the money flow. People want polished products and that costs money. The centralised platforms we have today have succeeded because they figured some funding. Achieving that in a decentralised world is the main problem we should be looking at. I'm afraid "just slap blockchain on it" is a highly detrimental approach, but I haven't seen anything more serious (not that I looked seriously).
Dislaimer: I'm in Google now, but this comment actually reflects my personal post-INRIA sentiments.