We _have_ standardized on Earth circumferences for length, only we divide by 40 million to make the numbers more sane, and got the measurement slightly wrong!
How hard would it be to fix this? Could we theoretically add or subtract enough material or make whole thing slightly more dense or less dense to compensate?
We should just redefine it to make the speed of light a nice even 300.000 km/s - we are so close already!