Making a native app is more complicated than making a webapp, especially if you want something cross platform. Browsers are now an universal virtual machine, what was the JVM years ago, and with webassembly we will se more and more things done in the browser.
The real 'write once, run everywhere' are webapps, a webapp doesn't care if you are using Apple, Windows, Linux, BSD, whatever, if you have a compatible browser you use the app.
Sure there is Electron (or React Native), to me it doesn't make sense, what is the point that every application needs to ship basically a browser? And still Electron apps need to be compiled and packaged for every platform, while with webapps you enter the URL in the browser and you are done with it.
Doesn't adding APIs to browsers not only to use the local storage but also to access the filesystem of your device (of course asking the permission to the user) make more sense?
Of course what really Apple fears is loosing the control of the apps that gets used on their device, now they control the App Store that is the only way to get apps on their devices (beside jailbreak), with webapps is different, since you can access them directly from the browser.
And the thing that is absurd is that the first iPhone didn't have the App Store since Apple decided that the only way to get third party apps was trough the browser, now they are aiming for the opposite thing.