Most of the festivals I go to are what you might class as smaller ones, just running over a weekend, but I do go to a few of the bigger ones. ALL of them depend on a vast amount of goodwill from volunteer organisers and helpers. Many people who are happy to help as stewards do not want to get involved in the main management of the festival but are happy to turn up and do as asked of them.
I had no specific training or experience in organising festivals when I came to it: I just had a huge love of the music and the festival, and wanted to give back something. My day job was in no way related, but did involve some management and organising and PEOPLE skills (also not trained to do but learned as I went along!) I learned an awful lot on the job, and tried to set down in writing for other Committee members any policies, risk assessments and guidelines for future incumbents. I did not want to be seen as a figure-head, but rather that I was pulling all the loose threads together into one coherent mass, with the same aim of getting out a good festival.
You soon find out who does not respond to emails, or say they'll do something and then don't, or even people who are allocated duties and then don't turn up. You maybe don't delegate enough for these reasons, but the job gets done, and you hopefully keep everyone on side on the way.
You find out that, on the whole, your great heroes and heroines that you have booked are nice and reasonable people, even if sometimes their agents are a bit over-zealous in the quest for riders. Again the people skills come in, in working around any perceived unreasonable demands.
There are always ups and downs on organising committees but the PEOPLE bit is finding a way through without alienating anyone.