Imagine, no countries
Imagine, no religion
...People living day to day
All religions are not equal because at least some of them represent a false (even if well intentioned) path.
In the end it’s implausible. The constructs of atheists are shallow and brittle. Spirituality comes knocking on people’s doors and gets let in, and people find it has far more heart. Sometimes it even manages to look like a pretty good parable of Christian belief. (That’s my impression upon looking at the modern anime tale of Pegasusa Fantaju, i.e. Pegasus Fantasy, that even has “Saints” who are on a journey of celestial achievement.)