Why would anyone give credence to such a rumor? Moshe Rabeinuwas willing to sacrifice himself for Klal Yisrael; he was the one who pleaded on their behalf after cheit ha’eigel. Does it make sense to think that he was out for the money?
“Ain ani eleh b’da’as.” A person can suffer a poverty of brains. A person can also have a richness of intelligence. Sefas Emes (Likutim) explains that there were those who charged that Moshe Rabeinu was rich in ruchniyus, in da’as, because he had worked on the Mishkan. It was not the money they were complaining about, but rather the spiritual weath, which they charged he had "hoarded” for himself. Therefore, Moshe gave an accounting. As we explained yesterday from the Kotzker, this was not a fiscal report, but a spiritual inventory, e.g. Ploni’s kavanos and l’shem shamayim created the kedusha of the aron; Ploni’s nedivus lev and retzinus went into the Menorah, etc. Moshe Rabeinu proved to every person that he/she was connected directly in some way to the spiritual riches of the Mishkan. The "wealth" was theirs alone to benefit from.