There are plenty of airfields that could host the event, but the cost of putting on such an air show is way in excess of any likely income. It certainly doesn’t makes sense to be based at Duxford and hold an air show elsewhere, with development threatening so many other airfield basing elsewhere is precarious.
Most likely opportunities to fly during Duxfords regular events will be offered, using existing crowd control, insurance and traffic arrangements, thereby avoiding expense of special event costs.