The key bullets are listed at the top:
1. data co-located with its UI
2. works offline
3. synchronizes between clients
4. lets its users own their data
So, except for #3, exactly like classic desktop apps that store data in local files. (#3 used to be called "peer-to-peer networking").
The modern equivalent of classic desktop apps (not that they've gone away) are mobile app stores. Mobile apps are installed and run locally on a phone, even though a key part in their business model is that most frequently sync back data to their server-side.
What's technically different between these and "local-first"? Nothing.
In #4, there's only an implied contract (not even explicit) that the local-first will be not doing "bad" things (like connecting server-side and then sending data there without user permission.) There's no technical limitation that keeps the app from doing that, though.
In other words, "local-first" seems to be a somewhat meaningless buzzword or critique about a business model, not a technical design.
1. data co-located with its UI
2. works offline
3. synchronizes between clients
4. lets its users own their data
So, except for #3, exactly like classic desktop apps that store data in local files. (#3 used to be called "peer-to-peer networking").
The modern equivalent of classic desktop apps (not that they've gone away) are mobile app stores. Mobile apps are installed and run locally on a phone, even though a key part in their business model is that most frequently sync back data to their server-side.
What's technically different between these and "local-first"? Nothing.
In #4, there's only an implied contract (not even explicit) that the local-first will be not doing "bad" things (like connecting server-side and then sending data there without user permission.) There's no technical limitation that keeps the app from doing that, though.
In other words, "local-first" seems to be a somewhat meaningless buzzword or critique about a business model, not a technical design.