Both articles use 2017 as the turning point date. TTS is a lot older than that. It's not difficult to find data to fit the desired point if you choose a narrow enough time range. Or location selectivity - both of those are just about the United States.
uh
https://news.harvard.edu/gazette/story/2025/09/whats-driving...
https://literacybuffalo.org/2025/01/23/adult-literacy-rates-...