Why is backbone bad, why has it lost its popularity?

Question

backbone.js

Why is backbone bad, why has it lost its popularity?

Answer 1

Out of the box, there is no point updating of the DOM tree (only re-rendering of the entire view, which is unproductive, plus problems like loss of focus in inputs). It is possible to fasten ractive/rivets/knockout, but all this is somewhat crutch.
Problems in models with nested objects. There are also crutches.