Why there is no Hindu Avatar story outside India? Why all carriers of Avatars are animals found in India only?
Thats because the concepts native to Hinduism originated in India. Hinduism is full of philosophical concepts and Mythology. Vedas teach worship of devatas (Indra, Agni, varuna etc) and some philosophy is found in it which is known as Monism. Then during upanishadic period this developed in to Monistic Idealism or Idealistic Monism. Then came the period of Mythology (Puranas and Itihasas). Thus all these developments are Indian thought and native to this land.
So Obviously Hinduism is favored in India.