Native code is already heavily used in the form of iOS apps, it just isn't part of the web. I am not sure that this distinction is particularly profound considering how reliant the app ecosystem is on the internet. What iOS offers are basic guarantees about the capabilities of the underlying hardware. Web apps can make no such assumptions, regardless of how cleverly they execute the code. So for native client the application will never run fast enough for a significant number of users despite the design goal of increased speed. Unless the app has latency or bandwidth constraints it will always be more reliably faster to do resource intensive work on a server.