While the 222 is more accurate, like the 308 is more accurate than the 30-06, it is one of those on paper things and does not show up at the range.
The 222 is a great round, my Uncle Ron hunted many white tails in NY with it when I was growning up.
With the Black Rifle explosion of the last 30 years the 223 has won the popularity contest and if you walk into to a gun shop you have at least 4 choices of 223 ammo ranging from 45 grains to 70 grains with many different styles of projectiles, and if they have any 222 you will have at best one loading.
Had Eugene Stoner and Nato opted for 222 in stead of 223. It would be the dominate round. Much like anything if the military adopts it, it will be popular with sportsmen and hunters.
And no one mentioned the 222 Rem Mag in this either.