You seem to be operating under the assumption that the inch, foot, yard etc were pulled arbitrarily out of thin air by a king when he standardized the system. No, the system already existed, and it had been developed organically by working people for thousands of years. All the king did was come in and say “we’re going to use this specific version of the system for standard’s sake”, he didn’t make any meaningful changes to the lengths themselves.

You put far too much emphasis on the so-called “immutable aspects of the universe” that metric is supposedly based on. At one point in time the meter was based on a metal rod that they kept in Paris, they only stopped using that because they found that it was slowly shrinking over time. There’s no reason that you couldn’t determine what fraction of a light-second that a yard is and then retroactively define it as that, and then claim that the imperial system is “based on immutable aspects of the universe”. It’s all arbitrary at the end of the day.