They have been around for over a decade. Ghost, strapi, grav, etc etc.

Many are far more user-friendly than WP. All are more secure, better performing, most easier to develop on¹ and several have far better fitting architectures and concepts for common use-cases.

Yet WP continues to churn along. It has it's "marketing" going for it. It has a familiar name, it is predictable (you know what cr*p and legacy you're signing up for, as a techie), and therefore it remains a popular choice. Which is a metric many people use to choose a tech stack on, so it's a flyweel.

You've probably not heard about any of the simple, secure, fast, static-file, build-on-CI, nice-UIs CMSs out there. They are there. You can use them to replace your WP. Yes, even if you have a staff of 20+ web-editors that have never even heard about something like "CI", "Git" or commandlines.

¹ I've been Drupal and WP developer from early 2000-s to early 2010-s. I've founded a few webhosting companies specialised in WP hosting. I've helped hundreds, maybe thousands of ppl with "WP stopped working last week, can you have a look". WP development is a ghetto full of dumpsterfires, with, if you know where to look, are very disciplined, avoid 95% of the "streets" (ecosystem), some gems.