It would be interesting if we could learn more in-depth details about why they prefer Classic Editor to Gutenberg, especially given the Classic Editor’s limited potential.

I can understand complaints from those who are used to their Premium Theme’s Page Builders and Gutenberg gets in the way. On such a large scale project, though, I assume that there will be a custom implementation, where Gutenberg shines, allowing you to build really cool stuff.

On top of that, Gutenberg content can be easily migrated on a future redesign compared to shortcodes (which can easily cause a huge mess), allows you to write the cleanest HTML possible, and the frontend output is much faster, as most of the time there is no need for storing data in meta fields, with everything remaining on the post’s table.

I assume that it’s about accessibility issues, but it would be interesting to learn which in particular, and how the Classic Editor is better at dealing with them.