> The motivation behind MVVM appears to be to update the UI automatically when data changes. Modern frameworks are moving away from two-way data binding (React, Angular 2.0, Ember, etc.)

Angular still has ngModel according to its docs. Whether you have two-way binding or not, View Models are still useful. Cycle.js doesn't have two-way binding but uses Event Streams and has a pattern that is similar to MVVM (they call it Model-View-Intent but the Model is a View Model by normal definition).

React not having something like MVVM makes it difficult to create reusable components. Most React apps are divided into the view layer (which are "components" but really just dumb views) and application logic which lives in the flux layer. This division means you can't / shouldn't write components that fetch their own data.