Whenever someone comes up with this suggestion, I never hear them mention the cost of all the changes in tooling. It's hard to find 13mm steel plate rolling mills in this country. How many machines are calibrated in inches? Every manufacturing line in the country would have to be replaced. I wonder why that little fact always seems to slip through the cracks?
Their reply would be “think of all the jobs we will create by trashing all the existing tooling and replacing it.” I would assume all the jobs would go away and never come back.