I’d argue the causality runs the other way. The popularity of YouTube, TikTok, Instagram, and casual games is a consequence of declining literacy, not a cause. The real cause was the abandonment of phonics in favor of whole-word approaches to teaching reading in the early 2000s. Those kids are now in their mid-20s and making their own purchase and usage decisions; with poor reading skills, is it any wonder that they prefer video and image forms of media?
The timing doesn’t really line up for the screen time hypothesis. Tablet mobile games became mainstream in the mid-2010s; the kids who grew up with them are now about 15 and younger. We’ve been seeing an inability to grasp complex written discourse and perform critical thinking since about 2016; the kids on tablets would’ve been in elementary school then, but the first cohort of students who grew up with whole word reading methods was just entering adulthood.
Teaching phonics is good, but your history is off by about a century. The abandonment of phonics happened in the late 1800s and early 1900s. Whole word approaches with readers like Dick and Jane dominated 20th century reading instruction in the US. 4th grade reading results kept going up all the way until 2017. https://www.nationsreportcard.gov/reading/nation/achievement...
its not only mobile games, it is proliferation of youtube and stupid streamers targeted for kids (colomelon and alike for elementary kids) and social media for middle schools (snap / tiktok)
The timing doesn’t really line up for the screen time hypothesis. Tablet mobile games became mainstream in the mid-2010s; the kids who grew up with them are now about 15 and younger. We’ve been seeing an inability to grasp complex written discourse and perform critical thinking since about 2016; the kids on tablets would’ve been in elementary school then, but the first cohort of students who grew up with whole word reading methods was just entering adulthood.