More Gambling.

He has spent most of the time in the egg within this mental space. It appears to him as a large, dark, and empty world filled with stars of various colors and sizes.

The stars are the imprints of every dragon that passed the naming ceremony and was given a name by the dragon spirit. They are all connected by an invisible spiritual entity, which makes the bloodline space look like a river of stars.

He has been going upstream of this river, looking for the special talents that he needs. It is a good use of his time. The alternative is to hatch now, but he can't do that. 

As he is currently, he ought to have hatched 50 thousand years ago. Normal dragon eggs spend ten thousand years in the egg, but he has already spent six times that amount of time in the egg. His littermates have grown up and have left the cave. Even his mother has forgotten about him.