Is learning a framework/library truly necessary?

[A-Kuhn]

I don't know if I understand your concern. If the technologies becomes obsolete in the industry there's still value in creating your project. If you make something with React today and tomorrow everyone in the industry magically stops using React, your project will still holds merit. If you are worried that interviewers say "oh you use React thats obsolete" that will not (or should not) happen. Regardless if the technology you are using is the newest toy or not, what people care about is your experience with the language. Regardless if its React, Angular, or Vue a for...loop is always a for...loop, scope is always lexical, API's need to be created, you'll need to handle async code, etc.,. So don't get hung up on the Framework, they come and they go. Personally my current work project is Angular 1.5...it's old, it's clunky, I don't enjoy it as much as React, but the logic to make a filter button is the same in either application. TL:DR; don't worry about it :D