I wonder if it is from the time of the illustrious Jeroboam II that literacy took off in a bigger way.

In earlier times such as Joshua's, writings were a training aid to oral proclamations. (Certain brahmins use Sanskrit thus to this day.)

Finkelstein and Sober are fudging the issues to some extent. Certain narrative details were simply passed down mainly orally for a longish while and more people joined in on the writing side at around the period already estimated.

Some of these types try to sell a story to the press as a sensation. To me, these are good finds in themselves and disprove nothing.

Additionally this news may have suffered in editing by our journalist or publisher (as is sadly often done with science stories).

It doesn't seem to say what the texts were - unless I've misread - nor whether they were of a kind one would expect to be written on pottery instead of another medium? Were they economic in character - contents of jar?