Per the comment thread, this doesn't have perfect explanatory power: drivers and ATC have also recorded statistically significant declines over the same time period.
In other words: remote schooling may have had a negative effect on ACT scores, but all evidence points to it not being the only (or even primary) effect.
In other words: remote schooling may have had a negative effect on ACT scores, but all evidence points to it not being the only (or even primary) effect.