The US has been the biggest obstacle in getting the known universe to adopt metric. Once we get you to accept the rest of the world has changed and that your steadfast adherence to an archaic English system (wasn't there a revolution on following English standards?) you and the rest of the work will save money and it will be easier to sell American Cars in Europe.

We tried to go full metric in the 70's but the huge amount of US manufactured goods stifled that.