The author doesn't understand the primary goal. It's precisely to have global consensus that proceeds according to its logic - so if you own something it can't be taken away from you. Everyone running their own private blockchains isn't decentralization, it's federalization. In the internet context, we know exactly how it would look like - initially an ecosystem of independent forums, each a fiefdom of the moderating caste, or subreddits on an alternative reddit that doesn't have global administration.
Network effects would inevitably concentrate most activity to few hubs (which is how we ended with facebook, reddit, and twitter consuming the old internet of phpbb forums). Except instead of posts, now the new powers-that-be would have absolute control over people's wealth. What he in effect, unintentionally, proposes, is to give the equivalent of facebook absolute control over people's wealth.
In fact facebook itself tried exactly that with Libra - but fortunately got shut down by governments.
Honestly, I would prefer a state-run blockchain over the inevitable final form of his proposal. At least it would be regulated by actual laws instead of T&C that give the company near absolute power.
There were crypto experiments of this type, most notably EOS. They had their own 'court' that ended up blacklisting dozens of addresses based on weak claims of theft. Eventually all DPoS networks are going to decay to something like that - because with just few publicly known validators escaping legal liability for not enforcing confiscation and freeze orders from real world courts is impossible.
The scalability argument is true in isolation - everyone agrees it's currently a problem, but has nothing to do with centralization or not.