His Holiness was never considered King of Tibet though he had temporal power which means political power. He has not abdicated but given his political power to the democratically elected Prime Minister. The Dalai Lama crowned XVIII DHarma King of Tibet, His Majesty King Lhagyari Trichen Namgyal Wangchuk in 2004 after his father the XVII King passed away. The King is being mentored by His Holiness and is studying in the US and surely will have a very important role as constitutional King of Tibet.
HH Dalai Lama is always picked. There are a serious of tests that he must complete. I have met people who helped and witness along the journey, since this position is Felipe's and enlighten. Not one that's born into like a monarchy.