Thin clients that verify transactions are possible though. For something like Bitcoin you have SPV-proofs that prove chains of headers. You can prove that a transaction was included in the longest chain without having to run a node yourself just by checking proof-of-work merkle trees; Even if the vast majority of users end up running clients that don't verify the whole chain -- cryptographic trust would still be ensured by checking headers. This requires no centralization.
Satoshi wrote about this architecture early on in scaling the blockchain. Ethereum also allows light clients and I think it even has checkpoints that make downloading headers faster. Cryptographic protocols that verify smart contract results could be included in Metamask. I feel like not mentioning this in the essay shows a lack of familiarity with the literature even if he was extremely opened minded (enough to create dapps himself.)
He did make valid observations about third-party trust: OpenSeas and Infura. But in both cases: these protocols can be implemented without centralized architecture. A decentralized alternative to Infura (that provides reliable results to users and easy-to-check attestations) is possible to build. One should also note that in blockchain land the lack of incentives to run a full node is a problem people are working to address. It's actually a perfect illustration of how the blockchain can lead to emergent systems. Some ledgers already have rewards for running full nodes. So yes -- people do want to run full nodes -- they just want to be paid for it.
I understand the criticism to be targeted at the "web3" idea, which is assumed to be about the infrastructure for decentralized applications.
What is possible to implement is less relevant than what is likely to get implemented: here the clients (read: the app on the mobile) and their means of accessing the decentralized goodness matters.
The argument as I understand it is: if access/usage to whatever decentralized goods is always mediated by the old centralized approach (you have to ask the server whether the transaction is valid) then you trust the operators of the servers and those folks have the option of making "everything" (access to those services/goods) faster & better.
It is like the "last mile" problem where a company may well operate a global network but have no setup to act as ISP for end consumers, which is left to mediator. This is compatible with "web2" (https vpns etc) but the "web3" answer seems to be missing.
The problem is that benefits of well-thought out incentive systems evaporate when access is mediated. If every dapp comes with its own mobile client and app-specific servers to address this, there is nothing decentralized about it.
Satoshi wrote about this architecture early on in scaling the blockchain. Ethereum also allows light clients and I think it even has checkpoints that make downloading headers faster. Cryptographic protocols that verify smart contract results could be included in Metamask. I feel like not mentioning this in the essay shows a lack of familiarity with the literature even if he was extremely opened minded (enough to create dapps himself.)
He did make valid observations about third-party trust: OpenSeas and Infura. But in both cases: these protocols can be implemented without centralized architecture. A decentralized alternative to Infura (that provides reliable results to users and easy-to-check attestations) is possible to build. One should also note that in blockchain land the lack of incentives to run a full node is a problem people are working to address. It's actually a perfect illustration of how the blockchain can lead to emergent systems. Some ledgers already have rewards for running full nodes. So yes -- people do want to run full nodes -- they just want to be paid for it.