Yes it is unreal and not convincing that Sa still remains a spoilt brat, given that Shekhar family is conservative (for good reasons) in its own ways.
The way the family operates, there is enough independence and individualism in their household, but at the same time they do believe in traditions, customs, society and culture. Based on that, after SaJa drama, Ira-Alok should have thought of reforming Saanchi and honestly that would have been the way to go.
But CVs want a negative character so they have left Sa as is. Besides which Sa is too smart to cone anyone or too sharp to throw away all those who she thinks are interfering (Anandi, Shiv lately, her friend Payal etc.) Also due to recent tracks of Shiv's identity and Anoop's entry the family has forgotten all about Sa.
I think Sa's scandal with Saurabh will give one more track to CVs and probably there after Sa will change - this time with Anoop's interference, I think.