To me the core problem wasn't with the data model, it's just that a declarative approach to binding events and reactive updates that knockout, vue, react, etc.

To me the core problem wasn't with the data model, it's just that a declarative approach to binding events and reactive updates that knockout, vue, react, etc. provide reduces significantly the amount of repetitive, boilerplate code that you need to write. All that searching for nodes, adding handlers and callbacks, then updating the DOM when data model changes is now handled by frameworks. As you've said, this is not really jQuery vs React issue at all, jQuery just provides some nice cross-browser shortcuts. The main problem IMHO in jQuery era was in keeping the binding/callback logic separated from the html templates that define the dom structure itself. In big apps it made it difficult to follow which code binds to what part of UI, and there was no way to prevent someone from binding to the same node you're working on from some completely different part of the app. Now with declarative approach it's all in the same place and it's immediately clear what handlers you have in place on any html element, making refactoring much less stressful.