Let's expand the question to include all Jewish leaders in every generation. After techiyat hameitim, the resurrection of the dead, Moshiach will continue to lead all the Jewish people from all past generations, including the leaders of those generations. Will all those leaders simply live in the shadow of King Moshiach? Will they have any standing at all?

The answer is that there is no such thing as a "past leader." A leader, or Rebbe, of a generation is a level that once attained, cannot be lost. This is true particularly of the era of Moshiach, when all Jews will be elevated; how much more so will our leaders be elevated and won't be demoted to a lower level.

The spiritual status of the Jewish leaders will remain and will be expressed by each leader in relation to his people, who will arise with the resurrection. As the Midrash says: "So says G-d to Moses: If you will be buried [with your generation] in the desert, they will come in your merit and you will come in their merit... in the future." Moses will be the leader of the generation of the desert, and Joshua will lead the generation that he led into Israel, and so on for all the leaders of all time.

Moses, in addition to being the leader of his generation, has a special status as the lawgiver: the one who transmitted the Torah from Sinai to the entire Jewish people, for all time. As the Lubavitcher Rebbe writes: “The quality of Moses as the receiver of the Torah is relevant also for the time after the coming of Moshiach. As is known the saying, that the giving of the Torah was a one-time event and will never occur again, even in the world to come. This means that even though ‘A new Torah will come forth from me,’ nevertheless, there will not be another giving of the Torah” [because the teachings that Moshiach will reveal are part and parcel of the Torah that we received from Moses].

Devarim Rabba, Parsha 2:9. Sefer Maamarim 5656, p. 356. Toras Menachem 5745, Vol. 5, p. 2619, 5751, Vol. 3, p. 280.