What are the consequences of the 14th Dalai Lama being the last one?

The current (14th) Dalai Lama has recently indicated that he may be the last person to hold that title . Does this stance cause any theological issues for the Gelug branch of Tibetan Buddhism or more widely Tibetan Buddhism in general? Can a tulku stop reincarnating? Does this potential lack of reincarnation conflict with the Bodhisattva vow? I understand that there is a political element to this but I'm trying to understand the consequences if any for the tradition, theology and philosophy of the religion.