As has been said, the entry fee is to raise money for charity. All aero club members not officiating paid for entry as did people who work on the airfield.
The attendance is the biggest in the Airshow's history, so a lot of people voted with their feet that the entry fee was reasonable. Traffic was a bit of an issue early on. I understand it was exacerbated by some local residents protesting early in the morning.
These type of events are important to demonstrate to the community that airfields do good things and demonstrate that we are not elitist, selfish rich guys with expensive toys. We all owe it to ourselves to support community events like this because it helps keep airports open.