> The reality is that even those of us who were taught cursive--Palmer script in my case--and can vaguely sort of still write some poor imitation of most of the letters, would generally struggle to read a lot of old documents.

Yes, I can attest to that. But it rapidly becomes easier if I stick with it for more than a few minutes. If you can read it at all, with effort, it's something you can acclimatize to.