I agree with todays quote of the day that besides Olympic Games and WC, no one needs a T&F stadium that seats 60k. But I like the approach that the French took when the build the Stade de France in Paris, with a movable stand to cover/uncover the track, allowing for more spectators for soccer/rugby (or other sports, like Football) and less spectators for T&F.
Total bullsh*t to plan building an Olympic Stadium and then tear it down, like Chicago was proposing.