Which Yahoo shareholders would be irate about, and the Yahoo corporation could not trivially afford to throw away regardless. That would have destroyed about 1/4 of Yahoo's profit at the time.

That would be bad enough, however the next step by the government would be to increase the fine amount, were Yahoo to hold out over time. Kick it up to $1 million per day and Yahoo would have folded no matter what. The problem is pretty straight forward: the government could push it as high as necessary to compel the result they wanted.