One other angle: They just kicked off a new fundraising initiative and are in the early phases of a long-range, programmatic upgrade plan. 3-yr extension pushes expiration out to 5 years, which is a nice round number to evaluate progress with the new initiative and reassess the landscape.
If the program is steadily improving or at the top by the end of those 5 years, a long-term extension comes. If the program is on par with today or declining, and a hot coaching prospect is available, maybe a change is made. If, like today, there is not greener grass on the coaching front, then a short extension gets done.