Mainframes -> microcomputers -> appliances (phones, tablets) -> whatever's next... (home servers?)
At some point it will swing back. It won't look exactly the same, but the industry will swing back. It might not be for speed, but as you say, for privacy. It's easier to protect data that is physically close to you.
We will probably also swing back from microservices with HTTP APIs towards monolithic applications. But that's another thread!
Unless legislation forces application providers to be accountable for privacy breaches, with tough penalties, I don’t see why privacy-sensitive users should forego applications that work with local files, moreso if those applications are free.
Unrelatedly, the author explicitly states that Electron apps aren’t real desktop apps. So he’s talking about native apps.