It was not the only movie, but it was the tipping point.
Sony paid huge amounts for jab tak hai jaan, fan, befikre without much returns. Even ek tha tiger and dhoom 3 sort of underperformed relative to their acquisition prices. Yrf had planning for more such big budget movies like shamshera, prithviraj which sony was not ready to risk. And u can see after record breaking ratings of war premiere how has star utilized it and not like it has used all films like that, it's handling of lakshmii , housefull 4 and baaghi 3 is commendable,but ultimately that movie didnt have that much repeat viewing. From sony's point of view only sultan and tzh had proven to be a value for money investment.So rather than putting all its eggs in one basket, it preferred spending on the huge t-series new movies library, where many may not be successful but atleast few can prove to be profitable thus reducing the risk ratio.