Because they are not the same letters and numbers (and the buyer wanted it) than the domain that sold.
That domain sale doesn't mean *all* CCN domains are worth the same. There are no general repeatable rules in domaining.
If the buyer was called, for example, Richard Ellis, he wouldn't want your domain.
If the buyer worked in, for example, Real Estate, he wouldn't want your domain.
You just have to wait and hope someone wants it.