I don't think anyone is suggesting that people owe anything: it was possible to keep to oneself in public spaces even pre smartphones. At the population level

I don't think anyone is suggesting that people owe anything: it was possible to keep to oneself in public spaces even pre smartphones. At the population level though, a shift in norms and behavior means that even two people who would be fine engaging with a stranger now do so less. To be concrete, it has less to do with forcing anyone to do anything than with changing the environment such that, across the population, it's harder for those on the margin to interact socially.