Why on earth can't we just agree to use the metric system?
Because the metric system is dumb. And the metric threads are not as good, strong or durable. I can prove all of this, but it really gets tedious and metric threads work good enough.
When science figures out that the universe is base 12, and so using a base 12 measuring system makes so much more sense, what will become of the metric system?
:-) At least it seems the world of cameras is base 12.