"just roll it out and make everyone do what we did" is precisely the mechanism that has saddled us with innumerable busted protocols and bizarre implementation artifacts.
It is also a way to essentially put your money where your mouth is, aligning interests and ensuring that you really believe what you're saying. Pushing out specs is a little too easy to simply delay others from doing anything.
Further implementations can be credibly compared and considered. Many "HTML 5" features came via Google Gears, and would have taken a decade the traditional paper route.