This site is built with Lym - you can build it locally to see how it works.
More detailed instructions are on Github.
Not all sites need to be "dynamic" - sometimes static is more than adequate to get the job done. Static is perfect for smaller sites that don't feed off a live database backend. It's also perfect for creating prototypes, and for managing templated HTML which could be passed on to a dynamic system like a CMS.
Resusing frontend code has always been tricky because of the difficulty defining the boundaries of what to share. There are several methods out there, Lym takes a fairly simple approach by forcing you to nest everything your module is, under a single folder, including how to fetch and build it. It supports intermodule dependency, Git-as-storage, semantic versioning, and automation.
Lym uses Handlebars, Sass and RequireJS because sometimes you need specifics to get something done. Lym could have used other frameworks, or could have tried to support every framework, but then it would probably never have been finished.