What dreadful hyperbole. If reading is in decline, it’s just that we are in a crisis of widespread ignorance and broken education system, but good luck navigating through life without knowing how to read.
The anomaly might in fact be that we are regressing in human general intelligence compared to the rest of history.
The European Dark Ages after the fall of Western Rome was a real thing. Many people regressed to the Stone Age for hundreds of years, and we lost almost every written work from ancient Greece and Rome. That can absolutely happen with the US and EU by 2200, especially considering digital information is far more fragile over centuries than papyrus and parchment.
Literacy isn't usually evaluated as a binary thing.
Here's how one organization ranks reading levels:
https://nces.ed.gov/naal/perf_levels.asp
I think the optimists in the article once believed proficiency was inevitable but maybe basic is the best they should hope for now.