The point I was trying to make was that on mobile devices where computing power and battery power is a limited resource, not only will it be running significant

The point I was trying to make was that on mobile devices where computing power and battery power is a limited resource, not only will it be running significantly more Javascript, but it would also have to render the view - effectively doubling the number of client-side tasks. If all the device had to do was consume HTML and render it, it would impact performance and battery life less. Also, if you build your entire page in Javascript, you could see as much as 50% difference in page load performance across browsers. Until most users that still browse with IE are on a version that is at least as fast as Firefox, you're allowing client experience to vary wildly outside of your control. Basically, you control how you serve your content, but you have no control over how fast the client builds HTML from server-data. In 5 years this may not be an issue, but right now it is. The more work you do on your own infrastructure, the more stable your service would become. Now, I'm still a fan of single-page apps, but for initial page loads it still makes sense from a performance perspective to render it on the server.