Many good points, but doing static sites like you do is an entire field of itself and not very well understood too, and you must expect some resistance from people who just want to carry on doing whatever they're doing.
What you write about caching rings especially loudly. Static sites indeed are a very interesting solution to these problems.
The reason this approach lost to dynamic rendering is the absence of any sort of logic that would rebuild _only_ updated pages.
The job of many, many web sites is to make it easy for people to add content to them. When adding something takes many minutes, the web site is doing its job poorly.
Things are around today that are fast and that even offer the logic I refer to above, but the ship has sailed. We largely live in a world of cached pages that are changed via a complicated database-driven CMS.
What you write about caching rings especially loudly. Static sites indeed are a very interesting solution to these problems.