Malbim: The Nasi's gift returns in Yovel, lest he take the nation's inheritance. If his gift would [permanently] transfer to strangers, he would need to extort the nation in order to bequeath to his sons. This is why he was given a share of Eretz Yisrael like one of them Shevatim, lest he need to extort the nation! Since he cannot give a permanent gift, he will bequeath his inheritance to his sons, and not take from the nation ¹ , like prior kings did; the nation was dispersed from its inheritance, due to fear.

Radak citing Targum Yonasan: Lemeinas'hon (to extort). This is like I explained "v'Lo Yonu Od Nesi'ai Es Ami" (refer to 45:8:2:2).