Of course that worsened things, but the article has tons of evidence that the deep changes happened before that–starting in the eighties to some degree when kids were less allowed free time outside (overall, of course there are exceptions), but dipping dramatically around 2008. Long before lockdowns. One of the author’s theses is that we are blaming Covid but that only exacerbated a strong trend already present.
Edit: wrong person quoted at top. This was supposed to be referring to quotes that it was mainly the lockdown affecting high school kids of the time.
To be clear, I strongly agree with @MaineLonghorn 's lament about kids not being outside enough.