Operating a festival is a great deal different to operating an air display accompanied by an exhibition in temporary accommodation. Whilst a festival stage may have an amount of electrical power and equipment exposed to the elements, Farnborough has a power demand equivalent to that of a small town and its many powered exhibits are susceptible to any electrical malfunction.
The exhibit halls are ranked on terraces with steep steps from some exits to ground level which, in a torrential downpour, have been known to take on the appearance of cataracts. They are also the highest points on the airfield.
Farnborough is not a gig where people are prepared to put up with rain, mud and faltering equipment. It is one of the world's premier airshows with everyone from heads of state to the interested enthusiast visiting and the major aerospace companies exhibiting and competing.
In my view, as a retired CEO of an international events company with 30 years experience of organising trade events around the world, some on airfields, I can tell you that the facilities at Farnborough are state of the art. The decision to abandon will have been taken by the organisers bearing in mind risk, loss of face and any monetary loss. As for curtailing the flying display, the flight crews, ATC and the CAA will all have had an input.
Safety is paramount, be it in the air and on the ground. If you think you can do better, I suggest you apply to the organiser, either for a position or a consultancy. I won't hold my breath.