Especially true since parallelizing the processing of transactions is orders of magnitude easier than parallelizing STORAGE of transactions in decentralized systems- he's deflecting the criticism towards an easier problem.
... which is the opposite of what a good engineer does. A good engineer focuses first on the hardest aspects of the problem, and tends to guide discussion there.
Getting a decentralized swarm to implement transaction processing is highly non-trivial, especially when (as the OP highlights) incentives are delicate and the entire system must be extremely secure.