Most of the world has had 1 meter spacing for all, a few places had 1.5 meters, and North America and the UK had 2 meters. Like everything in epidemiology, its all random.

A new study published suggests that 3 feet may be as safe as 6 feet, provided that everyone is masked.

Source: CDC is considering shortening social distancing recommendations for schools to 3 feet, director says

There was never any science behind the six foot choice. In fact, no one even knows who made it up. Like everything else in epidemiology, it’s bogus.

By EdwardM