Sixty five people might sound like a lot, but that might be because people are conflating 'outside broadcast' with 'current affairs outside broadcast'.
News and current affairs OBs can get away with a camera operator, boom operator, producer and 'talent'.
However, on a weeklong show such as this, there will be:
Presenters
Producer
Director
PA to the producer
PA to the director
At least three runners
Camera operators (x4)
Camera technicians
Lighting director
Offline editor
Drivers
Assistants to on screen talent
SME (subject matter experts)
Sound recorders
Sound mixers
Engineers
Graphics supervisors
Location manager
Series producer
Production Manager
Assistant to the Production Manager
Assistant to the Lighting Director
That's just off the top of my head. OBs need the same number of people to produce a show that studio-based content demands.