I choose not to buy at bike shops like @Wirt indicated, I feel like I pretty much know more than most the people in the shop and it’s frankly a waste of time and money at some point to bother using them as my source for bike buying when I can get the same information online while being less of an asshole and an annoyance to the staff. I know this is kind of dickish as well, but I sometimes ask the staff a question to “fact check” them and see if they are legit. However, some of the bike shops near me are pretty good and in general I find the mechanics more help than the sales staff, so I typically just hang by the mechanics if I need anything (and typically its a part/tool question).
I think for anyone deep in this sport and very particular, the shops are going to have a tough time serving these people. I know I am a PITA to them as I ask a ton of questions and get annoyed easily. However there are some times I ask general stuff to them and they are helpful (example experience with specific items, suggestions for tape/materials etc.). Unless your a dentist with lots of money to blow and you want to get your work done and ride without the headache, I think most high end folk already know what they want. I really don’t know what the right answer is but thankfully most people are not anal like I am… and I know I can be a pain to deal with.