People are people. They run the gamut in terms of knowledge and 'people skills' and I don't expect any to be an expert on everything. I was in sales myself for over 25 years in the photographic/digital imaging field (till I decided I had enough and got into IT) and I can say that while I tried to know my field well to answer the questions of pro photographers and amateurs alike I just don't know everything about everything. The trick is to try. Most LBS's have computers, and a quick check on the manufacturer's site can provide an answer like, which model pedal has more float? But don't expect them to know which, between brands, gets better reviews in the 'which has more float' question, however. That's your homework.
There are some good forums out there with review sections that I frequent to see what the complaints are about the hardware, if any, and sites like Youtube can have videos on things like adjusting shifting and brakes, if you want to be more self sufficient and not be a slave to an LBS for the basic stuff. So I have some tools and a bike stand so I can do those things and it has saved me some headaches.
Out here in So Cal, a new LBS just opened about a mile away (now I have 5 within about 9 miles) that has a good wrench and a good salesperson that I recognized from other LBSs. Right off the bat I trusted them to order and install new XTR Trail brakes on my SWorks Safire (that I swear I am going to be buried with when I die). They carry some brands like Jamis, that the others don't carry. Of the other shops, there are two that are also good, but not for the same thing and the rest I might go to if those don't have something I need. But no one shop is everything just as no one person is an expert on everything.
Tzvia- rollin' slow...
Specialized Ruby Expert/mens Bontrager Inform RXL
Specialized SWorks Safire/mens Bontrager Inform RL
Giant Anthem-W XT-XTR/mens Bontrager Inform RXL
Fuji Newest 3 commuter/mens Bontrager Inform RL
Novara E.T.A commuter/mens Bontrager Inform RL