Nah that’s not how that works. There are literally an endless stream of examples of the model providers tweaking backend stuff and improving prompt responses without using new or retrained data. And even if they added new training data to an existing model, it isn’t true to say that model ‘just came out’. But even then, when providers release better models based on new training data they release it as a new dot version, which boosts their sales from the announcement.
Fable has been out for more than a month - I didn’t have the preview version and I was using it around June 10th, when my Claude subscription expired. Saying “Fable only really came out 2 weeks ago” is just factually incorrect all around.
The preview models were not as good as the final release. Thus training must have continued after the initial announcement