Has anyone actually done a survey of where those writing content actually do that writing?

I might write a line or two direct into the WP editor. For that, it wouldn't much matter if it were just a plain text editor. (In fact, that's still sometimes what I use.)

But, for longer writing, I wouldn't dream of typing it direct into WP. I write it somewhere else first and then paste it in. Everyone I know who writes long-form work does the same thing (although they tend to use MS Word, whereas I use LyX).

How Gutenberg aids this process is beyond me. Will it, perhaps, stop mangling content pasted in from Word? (I see that this still happens, to the extent that there's actually a plugin to ameliorate this.) If not, why don't the developers address that important need?

I just hope they don't get rid of the HTML editor. That's where I paste my content so that it doesn't get mangled. In fact, I now use a filter to disable TinyMCE altogether in the admin pages. Will I have to do the same with Gutenberg? Or will they, perhaps, see sense and keep it only as a plugin?