The Shem m’Shmuel answers that had Klal Yisrael wanted it enough, Hashem would have given them all the ability they needed. It’s only “lo nasan Hashem lachem…” because Hashem does not give gifts to those who have no desire to receive them.
(This reminds me of the Maharal in Gur Arye in Braishis on the pasuk that says Hashem did not give rain because “adam ayin la’avod es ha’adamah” that one is not allowed (!) to do a favor to those who will do not appreciate it. This fits perfectly with the gemara’s (A.Z. 5a) description of Klal Yisrael’s sin here are being “kafuy tovah,” unappreciative of Hashem's gifts. My rebbe, R' Blachman, said in the name of R' Hutner based on this Maharal that since the biggest tovah you can do for someone is to give over torah to them, you need to first arouse their interest in the kashe or issue so it bothers them; if they don't appreciate what you are giving over, then it's is assur to give. R' Ya'akov Shapria quotes R' Kook as having a safeik whether there is lifnei iveir in causing someone to trip up in thier midos. Giving to someone who you know will have no appreciation might fall into this category.)