My feeling is that every serious programmer will end up inventing tools like this simply because the overhead of incorporating other people's tools eventually starts to overtake the overhead of maintaining one's own system.
That's the problem with Static Site Generators (SSG) in general. They're opinionated by nature and the learning curve could prove steep to process all the details of the configurations necessary to get the maximum mileage out of the framework but as you dig deeper and deeper, you realize that you'd be better off building your own framework that's fit to your objectives and use cases and improve and expand on that as…
I'm building my own productivity software program using Rails for this reason. I want to see only what I want to see on that page, I want nobody else's ideas getting in the way. It has an intended audience of exactly one, and will in all likelihood never acquire another user.