Chicken and egg, right? If Google declares it not ready for production, then nobody uses it for production apps, so it never gets the kind of testing it needs to really be production ready.

If Google declares it out of beta, then people assume nothing will change, and if things do change they complain.

So the current wisdom is to have a 'production ready beta' which indicates an in-between period where things can change, but you're encouraged and expected to use it in production.