What do people mean exactly when they bring up “Socrates saying things about writing”? Phaedrus?

> “Most ingenious Theuth, one man has the ability to beget arts, but the ability to judge of their usefulness or harmfulness to their users belongs to another; [275a] and now you, who are the father of letters, have been led by your affection to ascribe to them a power the opposite of that which they really possess.

> "For this invention will produce forgetfulness in the minds of those who learn to use it, because they will not practice their memory. Their trust in writing, produced by external characters which are no part of themselves, will discourage the use of their own memory within them. You have invented an elixir not of memory, but of reminding; and you offer your pupils the appearance of wisdom, not true wisdom, for they will read many things without instruction and will therefore seem [275b] to know many things, when they are for the most part ignorant and hard to get along with, since they are not wise, but only appear wise."

Sounds to me like he was spot on.

But did this grind humanity to a halt?

Yes - specific faculties atrophied - I wouldn't dispute it. But the (most) relevant faculties for human flourishing change as a function of our tools and institutions.