What the feed changed, and it was not the habit

The habit is old. What changed is who you are measuring against.

For most of human history the people in your sample were the people on your street, at your work, in your family, at your masjid. A few dozen of them. You saw them on ordinary days, in ordinary clothes, having ordinary arguments in the car park.

Now the sample has no limit, it has been sorted so that the people who show up are the ones doing well at the exact thing you are anxious about, and you are seeing them on their best hour. Not their best day. The best hour of their year, chosen by them, and then edited.