FE Hoppy sums it up well. Also the trend in large fan engines over the last 30 years has been to move to smaller core driving larger fans which move a higher mass of air for a given size of fan (look at the latest GE90 and Trent 900 fanblades)
So if a core that has a higher TGT can be developed that has the on wing life, then it can be coupled to a larger fan to give an improved engine fuel burn.
Smaller cores running hotter driving larger fans = latest generation of large fan engine.
RBT.