Pickleball is still a comparatively young sport. I kind of like the fact that there aren't too many rules and that there is some room for creativity and innovation.
That said, the basic approach thus far has been to set guidelines and then approve specific balls (and paddles) that meet the rules. It seems to be working well enough.
It seems that particularly with paddles just having a few guidelines has enabled great advances in paddles. I think we're all glad that wood paddles weren't specified. As paddles improve, so does the sport as a whole.
The cream rises to the top. If someone makes better balls, others will follow.