This is just my point of view, I don't claim this as an answer for anyone but myself. However, back when I was using Android and Windows Phone, I found that carrying an extra large phablet like the Galaxy Mega, Nexus 6, or Lumia 940XL gave me a very useful middle ground for the use cases you quoted from The Verge. The phones were big enough that at first glance (especially the Mega) they looked like small tablets, and were socially acceptable in work situations. Likewise, they were still phones so they fit in my (admittedly large) pocket even with a thin case.

I'm on iPhone now and I've "regressed" back to a relatively normal phone size with the iPhone 7. I almost got a Plus but I had an iPhone 6 before that and got comfortable with the smaller size. I'd probably be fine with the SE at this point, but since Apple has dropped that form factor I'm not going backwards.

So yes, I can see a place for a folding device when one needs to carry both a phone and a tablet, but for me at least, I can move to a phablet for that.