Because that isn't how courts work: Wright claims to have $x billion bitcoins and so anyone suing him is legally entitled to take his word for it.  For it to be an issue in any civil trial the parties would have to be fighting over it.  Civil court exists to arbitrate specific disputes between specific parties, not to impose any kind of cosmic fairness.

In this case, all they were fighting over is what Wright owed the company of his dead friend.  And the jury found that Wright owed $100 million from plundering the company of vaguely specified "intellectual property" that wright pretended to be dave's company to get in AU court, and then wright sold to Calvin Ayre for a few million to form the basis of nChain.

The jury wasn't asked anything about Bitcoin other than how many dollars in damages the family was owed due to wright stealing Bitcoins from Dave and his company, and for that they decided $0  -- potentially because they correctly concluded that wright never had any.