I assume you mean NodeJS-based generators? Static site generators as a concept have existed since the very earliest days of the web. I worked on a team that used an in-house SSG to maintain dozens of sites years before NodeJS (or even V8) existed.

Jekyll uses Ruby, not node. I don’t know what all the others use, there are so many.

Sure, generating HTML via another language is not new, but SSG pushed back against the notion of using dynamic CMS systems (which were de rigueur in the early 2000’s) in favour of static pages hosted on serverless systems and like GitHub pages and S3, with content (mostly markdown) held in version control systems instead of a database.