I would suggest that post Shoreham, operators have never been more conscious of safety, regulations and currency.
Given that the Red Arrows have displayed at Farnborough for decades and the safety reasons cited as regards built up areas, major infrastructure, etc have also been there for decades, this is more about the cost of insurance, maybe the insurers have declined to insure.
Clacton, Brighton,Bournemouth and all the other seaside shows hopefully will continue with full displays but even these aren't immune. Yacht 1 Reds 0!