I don't get the analogy.

Guinness didn't want to make it public because he was afraid competition would start using it, and then lose his company's advantage.

In the current context, the retention didn't happen because of Anthropic. On the contrary, the company wanted to offer Mythos/Fable.

I think that is a little bit disingenuous, Guinness just saw it as a trade secret. Not something that was too dangerous to release to the public for the public's own 'good', just that it could be bad for their business.