The brand promise that you honour today, might not be a good enough promise tomorrow.
Somebody else might promise something better. The problem your promise once addressed, might resolve itself.
The world will no doubt evolve, and what you offer now, might not be seen in time, as being as useful anymore.
Even though you still work hard on the same commitments, your efforts fail to serve an audience who cares.
Developing a sense as to what kind of brand promise will resonate with the people that trust you today, in the future; gives you space to explore your future promise options and perfect your delivery of the right one when the time is right to present it to them.
This project takes a strong commitment to asking the right questions and hunting down plausible answers from limited factual evidence, but it is a project that will guarantee that you are worth more in the future than what you are today.