> who benefits from illiteracy?

Those already on top.

They can afford to educate their own line and hoard resources across generations doing so. They can fail as many times as it takes before they finally succeed because of this. They throw the bodies of the world at their problems until they are solved, which necessitates an uneducated populace that doesn't realize they're chattel and canon fodder to this purpose. A populace that fear collective power, that fears community beyond immediate family, that shies away from actions that would better the world in favor of actions that are less risky personally.

UNESCO published a report on the beneficiaries of illiteracy at global, national, and regional levels (1989):

https://unesdoc.unesco.org/ark:/48223/pf0000085962

Elites are always worried about the labor crisis - “nobody wants to work”. Usually this is about blue collar work, and their desire to underpay and overwork service/laborers.

Globally, this class of people definitely wants to reduce literacy to keep a stream of manual labor inflowing.

People who want to control the illiterate and subjugate their voting power to their own ends.

The number of vastly unequal societies throughout history who have banned the lower classes from learning how to read, or from any kind of education at all - beyond whatever narrow training will make them better perform their specific duties for those on top.

...and not just historically. Some societies where significant minority groups are banned from getting an education, in order to further perpetuate their marginalisation, still exist today.

The response to your comment thread here is some pretty high flying conspiracies. The thought that those in power would try and make the country illiterate is straight up ridiculous. That would completely undermine the competitiveness of the country AND the time line to get any benefit for the "elites or whomever is behind it" would be significantly long.

Now if you are talking about a country like India - sure I could see Modi doing that. In that case it would be more about restricting growth and investment into education then dismantling an economy built on knowledge.

> what logic leads to this conclusion?

Any decent book about Reconstruction and Jim Crow.

Hence book bans and torching, although it's backfiring because they're being too general to try and avoid coming across as too totalitarian, so things like bibles are being banned too. Whoops.

I should have said and, instead of for.

Undermining is a form of limiting, and limiting is a form of undermining.