In what respect? I'm a fan of his work.
Discussion
Solutions to the Byzantine generals problem such as Paxos or Raft are more general than blockchain. And other solutions to distributed computing problems exist like conflict-free replicated data types. My problem with blockchain is that it is an infinitely-growing public ledger, and that while bitcoin needed it, not much else needs precisely that. Many things may benefit from something *like* blockchain, but not actually blockchain. And for a decade people have been running around with a beautiful hammer (blockchain) looking for nails to hit, and not finding any interesting nails (problems) so they started creating nails so that they would have a use for their beautiful hammer.
Take git for example. It is both distributed and it has a blockchain. But it's not a bitcoin-like blockchain requiring some network of nodes and Raft to operate. Most problems can be solved more like git and less like bitcoin. Bitcoin is the only real problem I can think of that actually needs what bitcoin did.
He would argue the Bitcoin blockchain is the first and only open system solution to the Byzantine Generals problem. He would also probably go on to say its temporal structure enforces agreement on history. Neither of those outcomes are ugly.
If you have a reference I'd appreciate it. I believe Paxos is the first solution invented way back in 1989 but published in 1998. And Raft is technically equivalent to Paxos. I'm sure he's proud that such a solution is now widespread in bitcoin, but bitcoin blockchain isn't the first and only solution.
But these are solutions to the problem of consensus among bad actors. Do we need consensus in social media applications? The only reasonable place we might want consensus is usernames, not that we need them, but that users seem to want to declare and own a globally unique one and you would need a consensus system to give users what they want. But I'm not sure the juice is worth the squeeze, and petnames avoid all the trouble.
If you are going to bother building a network of peers, a consensus algorithm, and an ever growing blockchain, you'd better be solving a problem that is worth all that trouble. Bitcoin clearly was. Usernames in a social media protocol don't seem to be worthy of such a heavyweight solution. I shouldn't have said "ugly", I should have said "heavyweight."
Theoretical solutions count for nothing. Only open systems impacting reality. But obviously technically you are correct.
And yes I agree with the overarching position that blockchain really only matters if you are solving for a fundamental truth of universal ongoing value.
I should also say that open timestamps are well solved by blockchain. So that's 3 things: money, timestamps, and universally unique usernames.
Neither Paxos or Raft count .. all these solutions assume a permissioned set of mostly trusted but maybe unreliable actors.
Bitcoin is in a different game; permissionless set of adversarial assholes.