I think their point is that in the end, most people want convenience. That convenience requires centralization, which eliminates a lot of the supposed benefits that something like cryptocurrencies were promoted with. We've already seen it play out very poorly several times in crypto already.

This adds convenience because I can instantly send ETH from Robinhood to PayPal to Coinbase to my Ledger, without dealing with banking rails or creating a taxable event.

I don't think convenience requires centralization. Centralization makes some things easier and other things impossible, and things in both of those categories can be useful for convenience. BitTorrent, the WWW, and VisiCalc on the Apple ][ are three examples of distributed or decentralized systems that were much more convenient to use than their centralized predecessors.