Board Thread:Boruto Discussions/@comment-5085906-20170430152255/@comment-5085906-20170505222829

Rachin123 wrote: ^Which exactly why I wonder why every Uchiha didn't awaken the Sharingan, especially considering how emotional they are. If Naruto Part 1 is to be considered (since most of the details from Part 1 have been later retconned) and what little we saw of the Uchiha clan in the Arc preceding and describing the Uchiha slaughter, there were some individuals who apparently did not possess the Sharingan. That also could explain how Itachi and Obito were able to take out the entire clan so easily. But, not every Uchiha's life was as unstable and intriguing as the life of the plot relevant Uchiha that we know and love (Obito, Sasuke, Itachi, Sarada - you know who I'm referring to), so it's possible that they lived their lives without abandonment issues or issues of the sort and didn't awaken their Sharingan.

Plus, I think if Kishimoto had given focus to average joe uncle Bob Uchiha, that would have ruined the infamous reputation surrounding the clan.

It is also important to note that Uchiha who had grown accustomed to constant war and strife were not as likely to awaken the Mangekyou. That could explain why there were so few Mangekyo users during The Warring States period.