The usual way to explain this away is that social capital was built while people could meet in person, and is now slowly fading away. I don't know how true that

The usual way to explain this away is that social capital was built while people could meet in person, and is now slowly fading away. I don't know how true that is; it could be completely true, or it could be just a false "fact" that pro-physical-presence people cling to. Another factor that I didn't consider is that there was basically nothing to do but work in many places - most things fun were either banned/shut down, or unattractive because they came with the implied threat of catching COVID. This includes vacation. I bet once recovery sets in, a lot of saved-up vacation time gets used at once, especially in countries and companies where significant amounts of vacation can be banked.