When building vanilla websites though, you are largely left to develop that structure yourself. These websites need Javascript but aren't entirely powered by Javascript. You can use tools and libraries (Grunt, gulp, bower, SASS, coffeescript, ...) but how you use them is really up to you. When the website gets large enough, these home-made solutions generally get complicated and difficult to maintain. There doesn't seem to be a framework or approach aimed at plain websites that don't want single page functionality.
How are you creating your website frontends?