though I'm not sure it makes any difference up front.
It doesn't.
In general, I don't think more money = more reliability when it comes to components involved in shifting. I think what you generally buy is lighter weight.
What you don't want is something that is "too cheap". Anyway, many "more expensive" components (105, for example) don't support the gear ranges that people want/need in a touring bike. And, given the abuse touring bikes can be subjected to, more expensive means more expensive to replace.
Touring bikes are a small market compared to road bikes: this means that touring bikes are going to be somewhat more-expensive for a given specification. "Better" specifications on the LHT parts would only make the LHT more expensive.