There are some okayish cross platform frameworks, such as QT and even JavaFX. One of the main complaints of cross platform GUI's has been that they don't work like native applications. But for some reason nobody cares when the app works like a single page web app, which in many cases is a lot worse than even plain old Swing apps. Which at least supports right-click properly.

I think the main reason that node-webkit and what-not are popular, is because of web developers moving to native app development. It's really easy to get started that way, and you can even share code with your web app. Where something like QT has a really huge learning curve for programmers transitioning from Javascript.

About poor algorithms. I actually worked on optimizing a well known web browser for a couple of years. And most of the stuff we did, was because of really bad Javascript code. Even though it seems gluttonous to embed a web browser in applications, and even insecure, it doesn't have to be as bad as it is, especially with a simple application like Spotify. This is going on a bit of a tangent, but every frontend programmer should at least learn how the browser actually works, a nice site for that is http://jankfree.org/