User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-203.59.104.107-20120718031524/@comment-4212769-20120727020907

It's not because of attractiveness. You need to see it in another point of view:

Do you know if a Rathalos/Rathian thinks that's attractive? Maybe it means: "I have much more experience. Stay away!" And knowing that they don't live in Forest and Hills anymore where Raths lay their eggs and grow their offspring must mean that they don't get youngs anymore. Which Rath-baby would like to live in a Tower with low access to food (the few Aptonoth in front of the Tower) when they can grow up in the Forest and Hills where the food sources are right before the "door"? For Rathian and Rathalos it's much easier, too having not too far to travel only to get the daily food for the youngs. Of course it has some risks like predators but I don't think that monsters would be stupid enough to provoke two breeding Raths. And Velocipreys are the only small monsters able to jump up the mountain (and Shakalakas) but I think the parents have a good eye on the babies.

Meaning either Gold Rathian and Silver Rathalos are a completely different subspecies, or they don't reproduce anymore.