When it became cheaper to publish text, for example with the invention of the printing press, the quality of what the average person had in his possession went up: you went from very few having hand-copied texts to Erasmus describing himself running into some border guard reading one of his books (in Latin). The absolute quality of texts published might have decreased a bit, but the quality per capita of what individuals owned went up.

When it became cheaper to mass produce sneakers, tshirts, and anything, the quality of the individual product probably did go down, but more people around the world were able to afford the product, which raised the standard of living for people in the aggregate. Now, if these products were absolute trash, life wouldn't make much sense, but there's a friction point in there between high quality and trash, where things are acceptable and affordable to the many. Making things cheaper isn't a net negative for human progress: hitting that friction point of acceptable affordability helps spread progress more democratically and raise the standard of living.

The question at hand is whether AI can more affordably produce acceptable technical writing, or if it's trash. My own experiences with AI make me think that it won't produce acceptable results, because you never know when AI is lying: catching those errors requires someone who might as well just write the documentation. But, if it could produce truthful technical writing affordably, that would not be a bad thing for humanity.