>>no one place can satisfy your criterion B, to fit 7 billion people. Fully agreed - exactly the point :-) For the foreseeable future, we'll have to live in h

>>no one place can satisfy your criterion B, to fit 7 billion people. Fully agreed - exactly the point :-) For the foreseeable future, we'll have to live in heterogeneous environments with limited "one size fits all" , or "implementable immediately by all" solutions :-/