Who when and why invented the metric? and why the US didn't adopted it?

Question

Who when and why invented the metric? and why the US didn't adopted it?

Answer 1

Base ten measurements have been around since the Babylonians created the concept.

The English are the ones who attempted to propagate their own unique systems based on arbitrary length and weight units.

And, the U.S. followed the English lead.  There is no need to continue these arbitrary unit distinctions, but custom and familiarity continue to slow our acceptance of the metric system entirely.