No, I'm not Jakob Nielsen.
I do however run a company that employs lots of blue collar, non-college-educated people, in manufacturing. And although this is in no way scientific, my experience matches this: most people are much more uncomfortable writing than they are reading. Even with reading, most strongly resist reading documentation unless they have to, and prefer trial and erroring their own gut instinct until they happen to find something that works or they give up. (This is less true of the most highly skilled technicians, such as those who troubleshoot robots and low voltage control systems.) The official statistics on literacy are absolutely not a good indicator of how comfortable people are articulating themselves with the written word, much less reading.
This is generally met with disbelief by most people in tech I talk with about this, because for the most part they have nearly zero interaction with this large portion of the population. From their daily experience, 98%+ people can make effective use of these tools.
But almost nobody in this partially literate population wants to write in an empty text box to ask an AI to do things. They can learn to visually navigate a simple UI, especially if it's well-designed, because they can effectively make decisions about what of several paths to take.
Some others here have brought up voice, and I do agree that voice is a more promising avenue, although I think it'll still take carefully constructed conversational experiences to work well (i.e., free form 'tell it what you want' will still not work).