My guess is that posting one's setup can be a little intimidating for some of us. Especially when you get a look at something like Mike Lavigne's setup (it's awesome, by the way).
Also, some people like to keep their lives private, which is 100% their prerogative.
That being said, posting one's setup can be beneficial. Especially when one is asking for advise on possible equipment purchases.
It helps provide a point of reference when it comes to budget and synergy.