If you're saying that Core Data locks you into the 'relational database' way of modeling data, that's definitely true. But, you're no longer tied to a specific persistence store. NSIncrementalStore lets you use whatever you want for persistence -- web service, JSON file, etc.
For a lot of applications, a relational model will work just fine. And, the optimizations that Apple provides for SQLite are probably going to be better than the average developer would achieve by writing their own SQLite transaction layer. (A little confused here on your point about needing SQLite at scale for performance -- it's the default persistent store on iOS).
I'm not sure I agree that an app needs to be wed to Core Data -- if the transactions with the persistent store are hidden from the model layer, then they should be swappable for something else.
For a lot of applications, a relational model will work just fine. And, the optimizations that Apple provides for SQLite are probably going to be better than the average developer would achieve by writing their own SQLite transaction layer. (A little confused here on your point about needing SQLite at scale for performance -- it's the default persistent store on iOS).
I'm not sure I agree that an app needs to be wed to Core Data -- if the transactions with the persistent store are hidden from the model layer, then they should be swappable for something else.