It is better to burn out than to fade away! What does that mean, huh? You have to admire Lance for knowing when to stop. But you should also respect those who kept striving for victory for as long as they could, using up every bit of energy and talent in their legs. Clearly, the training and dedication required now to win Le Tour is maximal. Any lack of commitment would show up as a loss, so the beter part of valor is to stop in conjunction with your willingness to train for that level.
Have you ever picked up or ridden one of the top end Treks? Man they are light and I'm sure they ride quite well. I'm not trading in my beloved Dragonfly, but Trek deserves respect for what they do.