In reply to Justin Mayfield.

Gutenberg devs obviously have "one-user-is-admin" sites in mind who spend time to fiddle around with the content again and again and update this and that every few weeks.

In reality most sites are not like this.

Most sites are designed by some agency and clients have a limited author account or similar to upload a new menu pdf or change some opening hours maybe once or twice a year. Those users will break everything if you allow them to use Gutenberg as admin, not because they want to redesign things and can't but just by accident.

Most clients invest an amount X to "have a website made". They do not have nor invest another amount X for continuous required technical changes and theme updates and whatnot so some full site editing feature works with whatever plugins which they both will never really use.

Thats the problem.