By which measure?
Endowment? Harvard, a DI (an FCS school).
Enrollment? NYU, sure, a DIII. But Stanford is smaller than UND or NDSU. Should they go DIII also? How about Duke?
I thought according to some DI is all about the prestige and glory of the higher level of DI athletics. If privately funded DU wants to spend private dollars on athletics to chase that prestige and glory, in a word, so?