Well I agree and disagree. Pros NEED to put on their best show in order to help sell their music and merchandise, but you have to consider many of those bands are suffering from jet-lag and having to deal with fans too. I hear some people stating that they don't talk to their favorite bands because they don't know what to say, but at the same time, the same goes for the bands, yet many of them hang out with their fans, and I am sure it is just as cumbersome for the bandmembers (if not moreso) than the fans, finding things to talk about. All of that stuff requires energy. Many bands also have to deal with things like merchandice issues, quick sound checks and frankly pressure to perform at events this large.
I have been in and out of bands over the last 20 years or so and it is fun, but hard work. Having saud that, the work was certainly not comparable to what those guys that played PP had to go through for their performances.