Interesting and thought provoking. Native may not be the best approach after all...
For many projects it is just a waste of time & money
What's a waste of time? A Multi platform product? Based on what are you saying this?
If user experience is your advantage, then you should go native. Some product like xamarin or nativescript able to provide standard native experience with little effort. You can call it write once read anywhere. But if you want big customize UI just like snapchat or instagram, i think there isn't any shortcut.