Why didn't the lionesses fight back?
I find it odd that during Scar's entire 5 year rule of the Pridelands, the lionesses didn't try to oust him even once. They may have had no reason to mistrust him in the beginning, but as the situation in the Pridelands deteriorated and Scar became more dictatorial and abusive, wouldn't it have occurred to at least some of them to drive Scar and his hyenas out? And I know what you're going to say: Scar was too powerful, and he had too many henchmen. But when Simba returned to reclaim his throne, they really had no trouble kicking the hyenas' butts. Why couldn't they have just done that earlier, instead of waiting for a strong male to arrive?
Maybe that's the answer, that the females couldn't bear to dispose of the monarchy that had held their pride together for so many generations. After all, kicking out or killing the king would break the traditional Circle of Life. That does seem a bit extreme though - the pride was literally about to die under Scar's rule, and rebelling still didn't cross their minds at all.
I dunno, I'm just throwing around some ideas here. Thoughts?
Maybe that's the answer, that the females couldn't bear to dispose of the monarchy that had held their pride together for so many generations. After all, kicking out or killing the king would break the traditional Circle of Life. That does seem a bit extreme though - the pride was literally about to die under Scar's rule, and rebelling still didn't cross their minds at all.
I dunno, I'm just throwing around some ideas here. Thoughts?

Anyway, I believe you already stated the answer as why the lionesses didn't stand up against Scar on their own. They needed a king to replace Scar after he and the hyenas are ousted from power, which they found in Simba as he is the rightful king that should be ruling the Pridelands. Also, keep in mind, real lion prides usually have 1-2 alpha lions to protect the pride from rogues and intruders, and maybe it is against the laws of nature (and maybe the Circle of Life) for a pride of lionesses to not have any alpha lion governing over them.
And after a few years, a male from...ugh, I can't remember the name for the group, but outside of said pride and he challenges the male for leadership.
I hate how whenever lions are mentioned things always become a gender war xD I'm obsessed with lions, my fave animals, so I like to study them ^^