Managing a website and writing for it are two different activities to me. I prefer to do the latter in a WYSISYG editor. I don't want to fire up a terminal to deploy content changes.
With proper caching, the output of a CMS can be indistinguishable from a static site, but it can also include RSS, pagination, categories, tagging, responsive images, tables of contents, etc.
Take https://allaboutberlin.com. In my browser, most of its pages load faster than the tiny website above. It has a big header image, custom fonts and other features. You can achieve great things with HTTP2 server push, static caching and gzip.
You should definitely consider making simple, fast websites because they're great for visitors, but how you produce the HTML doesn't matter.
Sure, but they need to be generated by some sort of framework, somewhere. If your definition of a static site includes framework-generated index pages and page structures, aren't almost all websites static already? Making them tiny is just a matter of writing better templates, not picking more obscure frameworks.
In my books the difference lies in how the HTML is generated. In case of static sites you generate it only when you rebuild the site after changes. In dynamic sites you build it dynamically on each request. Sure, you can cache the hell out of it and have a feeling that it's the same, but the truth stays that perhaps you're doing 50 SQL queries for a simple "welcome on our site" landing (something I actually witnessed some years ago). And with caching you're achieving the result with adding another infrastructure layer on something that could have been dead-simple from day one.
With proper caching, the output of a CMS can be indistinguishable from a static site, but it can also include RSS, pagination, categories, tagging, responsive images, tables of contents, etc.
Take https://allaboutberlin.com. In my browser, most of its pages load faster than the tiny website above. It has a big header image, custom fonts and other features. You can achieve great things with HTTP2 server push, static caching and gzip.
You should definitely consider making simple, fast websites because they're great for visitors, but how you produce the HTML doesn't matter.