WP should not overlook two other topics pointed out in their requirements:

“A flexible templating system that allows us to write any HTML we wish, with no or little interference from the CMS”

This is the exact opposite of what WP/Gutenberg does, and what Craft (using Twig or GraphQL) is built for.

“Internationalization”

This is where Craft is best in class, and WP offers exactly zero. (No, those plugins do their best, but cannot compensate without core support)

Personal note:

Add WP’s lack of support for complex, cross-referenced data models on top.

Plus the lack of an underlying MVC framework, making custom developments nerve-wracking and costly.

So i dont’t think it is only about accessibility.