i asked myself the same 2 years ago when my team was deciding if we need all of that javascript framework madness. In the end we built whole product based on dartlang (http://www.dartlang.org) which compiles down to javascript. We used only Dart language and no frameworks and best thing that came out of this is that we don't feel bound by restrictions of some framework but add stuff as we feel like. What we did is email marketing app https://www.listshine.com, something like mailchimp but faster and with less clutter.