NOT DUE TO LACK OF KNOWLEDGE

Boy is my head spinning on this.
Srila Prabhupada explains that the entire Yadu dynasty, offspring of Lord Krishna and His sixteen thousand one hundred and eight queens queens...sons, grandsons, etc... numbered in the millions. They were direct plenary expansions of Himself. They were not ordinary human beings. 

"The large numbers of family members [Yadus] born of Lord Kṛṣṇa counted to some millions and were certainly a great increase in the population of the earth, but because all of them were expansions of the Lord Himself by His transcendental plenary expansions, they were a source of great pleasure for the earth." SB 3.3.14 purport

Uddhava laments that the although this was the case they were not able to actually realize Lord Krishna as the Supreme Personality of Godhead. They simply thought pf Him as an incarnation of the supersoul. It was not due simply to the lack of knowledge. They were scholars of the Vedas.

"The Yadus were all experienced devotees, learned and expert in psychic study. Over and above this, they were always with the Lord in all kinds of relaxations, and still they were only able to know Him as the one Supreme who dwells everywhere." SB 3.2.9

and 

" The Yadus, therefore, accepted Lord Kṛṣṇa as the Supersoul incarnated in their family, and not more than that." SB 3.2 9 purport.

It was due to their misfortune only:
"This lack of knowledge was not due to their insufficient erudition; it was due to their misfortune." SB 3.2.9 purport