>I hope a static site generator comes along with an intuitive UI for non-technical people to easily update their own content.

Those people are already served well by things like Wix and Squarespace. WordPress is essentially a point and click application development tool at this point, with integrations for anything imaginable. Yes it is insanely insecure, slow, poorly designed, and bloated. But the depth of offerings from the plugin marketplace will keep WP relevant for a long time to come with people who can't afford custom development.