The app you're reading this on already has the button Australia wants to mandate. The Following tab shows a chronological list of only the accounts you picked, and it quietly flips you back to For You every time you close the app. Instagram's version does the same thing. That design is deliberate. Meta let academics run this exact experiment on tens of thousands of users during the 2020 election, published in Science. People switched to chronological feeds spent noticeably less time on…