"Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole (at sea level), its definition has been periodically refined to reflect growing knowledge of metrology. Since 1983, it is defined as the length of the path travelled by light in vacuum in 1 ⁄ 299,792,458 of a second."
Again from Wikipedia:
"The yard ...was first defined in law by Edward I of England in 1305, and again by Edward III of England in 1353. Edward I's law stated "It is ordained that three grains of barley, dry and round, make an inch; 12 inches make a foot; 3 feet make an "ulna" (yard)...."
Nothing make a meter less arbitrary or more useful than a yard, except that it is part of a base ten SI system (and that of course is very important in general, but not necessarily for athletics).
The different races are actually meant to allow contest by different sorts of running specialists, roughly short sprinters, long sprinters, middle distance, distance, and ultradistance. In these terms, we could just as meaningfully choose a range of distance. But we have settled on standard distances of 100, 200, 400, 800, 1500, 5000, etc.... This is all fine, especially for international competitions.
But sport is full of historical artifact (eg, quarter horses will always race one quarter of a mile- how absurd to change that to 400 meters), all of which enrich the experience of participation and spectating. The mile distance is just one of those.
What we are should be debating is whether running the mile frequently ( but no one said to the exclusion of the 1500) might help to increase the popularity of track in America. Not whether the 1500, 1600, or the mile are more or less sensible as racing distance.
Given the reality that track is not popular (despite the millions of recreational runners), is it not worth trying.
To keep consistency with the metric system, we ought to get rid of the 400, 800, and marathon too. Proposed standard distances: 500, 1k, 1.5k, 3k, 5k, 10k, 20k, 40k.