The title is provocative and borderline captious. CMS systems will of course never die, at least I hope so, designing and implementing them has given me work for many years and I think it still will, but for many of us they are a heavy element to manage, they distract from the objective like word processors. A frequent question is why use them when a normal text editor is sufficient for most tasks? For blogging over the years, I have tried a bit of everything: blogger, WordPress and others, in most cases static HTML is satisfactory for most of us, and it certainly is for my blog.
I have to say that, by pure chance, I stumbled upon a blog made with Jekyll while googling, so I started experimenting and was surprised: productivity skyrocketed, not only did I not need to be online to do everything, but I was doing it better because I was only concentrating on the content of what I wanted to communicate, plus hosting for static sites turned out to be cost-effective.