So why is that? This was my big head-scratcher with Ember; surely the access to a data layer is the whole point of these javascript frameworks? I mean all backbone is really is a layer between REST and client-side javascript. I guess i'm missing a whole class of JS applications that don't need access to a server-side data layer, but for me that's the fundamental reason to be looking for a JS framework in the first place. So to come across one so highly regarded which doesn't have it baked in was very jarring.
It's not 'baked in' because Ember is modular: Ember-data has all of that layer in it, so the rest of Ember doesn't have to care. That said, I disagree with your parent: you shouldn't be writing your own data layer.
But ember shines in other areas that people wont care about until they have to write single page web apps with a high enough complexity that warrants it. The reason we ditched gwt for ember was the 2 way bindings. Not having to write all that stuff(and test it(in every browser))has been a productivity boost, even though we had to plugin our own persistence layer.