The cost of a bike and components are best justified by utilization. If you don't know how to use it, who cares if it is a $5k bicycle.

For people just getting into touring, there are many awesome introductory bikes. You mention the Trek520. It is an awesome starting point. However, as people gain experience, they may find they want different components to be more comfortable or efficient touring. Going out and purchasing a $5k bike as a first touring bike w/o experience would not be financially feasible for most of us unless we knew exactly what we wanted.

Are the decisions on my touring bike the ideal bike for everyone? Definitely not. But I put in the time riding and touring to know that I made the correct decision for me. Based on your previous posts, you would think my bike is a POS, when I fact it is completely custom. Canti brakes! (OMG) One speed! (42x16? WTF) Steel! (Ancient material)

The worst bike you can buy is one that isn't ridden or breaks all the time. Just my opinion.