She Doesn't Have The Skills Or Power

Akeem's older sister, Salma is a very powerful and very smart young woman. She had high grades, the nobles loved her and the kingdom always praised her for her grace. She knows the ends and outs of the kingdom, preparing herself to be the next Queen's aide or a Lady of her own land.

If she had water elements and the right skills she probably would've been Queen right away. She was that promising. 

And she took the throne for the Queen seriously. She never wanted women that's in it for power. Or for the King's love and luxury. 

After all, no one wants a lazy Queen who couldn't rule the north side of the Kingdom without power and smarts. Or some woman who won't get along with the King because they wanted to take over.

That happened at least three times, either a King or Queen wanted to be greedy and rule the kingdom with their own power. Wanting the riches and influences that came with being someone so powerful.