This seems backwards. Access to Fable can be removed. I don't see how an open weight model can ever be put back into the bag though.

The model itself, sure; the comment is about the production of more advanced models (to keep open weights near the frontier).

Governments can always offer prizes, and any model that sufficiently meets the criteria of the prize would win it and claim a large cash prize. Once claimed, the model would then be free to all forever.

The proprietary spigots can be turned off at any time also. To me, that seems more likely.

I'd call 'more likely' an extremely safe take given that it's exactly what's happening right now