Approach of Star(as well as parent Disney) towards the next auction will be a key factor in deciding rights and price. If Star doesn't lost interest towards IPL then competition remain tough. Two things to note,
1. Even Star got huge viewership and revenue than Sony, while comparing with their expense things are not pleasant for the network. So its a question that Will Star keep the same aggressiveness this time?
2. Change in parent company - Fox was over fond to Star and Uday Shankar was very bold in taking decisions. When it comes to Disney, they are regulative in providing funds. Also executives of that time had changed.
Star's movement is unpredictable. After acquiring IPL and BCCI rights Star doesn't made any major event aquisitions till date. Sony bought so many cricket board rights and Viacom 18 also buying many many rights. So Star may comeback with a bang by retaining IPL rights.