The other thing is that really at this point block editors are everywhere; they are in every email marketing tool, they are in some social media sites, they are in other CMSes.

A block editor isn't optional at this point. Nor is block layout editing.

And pointing at a million people who install a plugin to keep the classic editor functionality is not the same as pointing at a million people who don't want Gutenberg.

It's pointing at a million people who have a variety of reasons not to upgrade older existing content to blocks, but who still need to edit that content (e.g. complex/ill-advised shortcode setups, specific markup etc.)

(The Classic Editor plugin is not either/or -- you can decide to use it per post or per user.)