If they tried to fill all of the 'downtime' they wouldn't be able to cover one single event properly, it would be cutting back and forth all the time, not good tele in my opinion. They have repeatedly made it very clear if you want to you can change channel to watch another sport. If the downtime annoys you press the red button or go online and watch something else.
The downtime also gives you chance to hear the opinions of the fantastic pundits and commentators the BBC has yet again. There are probably more gold medals in the studio than we will actually win out on the tracks. Steve Cram, Colin Jackson, Denise Lewis, Johnathan Edwards, Mark Foster and Chris Boardman etc have all been great as per usual. But I especially like our American friend Michael Johnson who gives some fantastic insight into the sprint races. I also thought Ian Thorpe was great during the swimming too. Two icons of sport that keep coming back to the BBC rather than their own US or Aussie channels and I seriously doubt the BBC pays them more. Why do they both keep coming back to the BBC?