In R. Jonathan Sacks’ 2019 Devar Tora for Parashat Pinchos, “The Crown All Can Wear”, he notes that Moshe fully expected that HaShem would Appoint Moshe’s sons as leaders of the Jews in his stead, and was brought up short when God Informed him that Yehoshua would take over the reigns. He cites a Midrash that distinguished between Gershom and Eliezer on the one hand, and Yehoshua on the other:
BeMidbar Rabba 21:14
The Holy One, Blessed Be He, Said to him (Moshe): (Mishlei 27:18) “He who keeps the fig tree shall eat its fruit.” Your sons (Gershom and Eliezer) sat idly by and did not study the Tora. Yehoshua served you faithfully and showed you great honor. It was he who rose early in the morning and remained late at night at your House of Assembly. He used to arrange the benches and spread the mats. Seeing that he has served you with all his might, he is worthy to serve Israel, for he shall not lose his reward.
This leads R. Sacks to engage in a lengthy reflection upon how becoming familiar with the contents and methodology of Tora was a great “equalizer” in terms of social status within Judaism. He states that while Jewish tradition certainly has its “dynasties”—the Kingship and the Priesthood, where a son inherits from his father– it also has a strong streak of egalitarianism—Tora scholarship, that is open to all.