It doesn't really make sense to call it vendor lock-in when you're learning a platform's native API and idiosyncrasies.

That would apply more to React Native since you are stuck with its vendored abstractions and you can't just swap out React Native once you've built with it.

I think you're commenting on how iOS development is a less portable skill than a toolkit than runs on all platforms. Or that your iOS app is stuck on one platform. That is certainly true. But don't overlook the value of expertise in a native platform instead of just one set of abstractions that run on top of it. There are things you can do on the native platform, like optimizing performance, that you can't do using something like React Native.

It's all just trade-offs.

> That is certainly true. But don't overlook the value of expertise in a native platform instead of just one set of abstractions that run on top of it.

This applies to the web, too. A dev who has a good grasp of of the fundamentals (HTML, CSS, JS), the DOM, what does and doesn't trigger a repaint, etc is going to be able to take a React project a lot further than a dev who only knows how to use React.