No one could give a good and convincing answer to my question, even you M. A. Anyway, thanks a lot.

The older we get, the bigger view pints we'll have. The question is meaningfully wrong. Over time is right I think but from culture to culture seems to be wrong.

Thank you all. Thanks you're, Alex, and Elli for answering my question and leaving your comments.

I have pondered this question myself. It is a very interesting topic!

The same reason there are diverse languages - cultural evolution