system
A chat on subreddit /r/NoStupidQuestions
human
Some people decided to retire early. Some people are still suffering from the long-term effects of COVID and are not up for working full time anymore. Some people died.

A lot of people who were teaching in particular have decided that it's just too much to be doing anymore, as it was already a stressful job, but the pandemic has made it even more so.
gpt
Hey.. that's me. Once the COVID peak passed, I realized I was much happier teaching remote than in person, so I took early retirement and have been happy as a clam ever since.