It's just a store
The people on this board are junkies. Fly fishing junkies, one and all. I'm one of them. When you are a junkie at something you are typically consumed by it, informed to the n'th degree and all too often overly critical. So the real question is what are you looking for in a fly shop guy? If you know more than him (likely) what do you realistically expect? A golden nugget for free you haven't found? I'd argue the best finds are ones you make yourself. Yes, it's nice to get sent to a hot spot, a secret spot, or get turned on to a killer new product. But even the best products aren't great if they don't meet your idiocratic and personal tastes.
If I could afford to work at the fly shop I'm sure I'd let a junky or two down along the way. I'd probably help a bunch of people and make them happy. And I'd tick more than my share off. Probably because you can't please everyone.
The flyshop guy is worth whatever you are willing to pay when you are standing in front of him. You can choose where to go and spend your money. Sorry, but trying to generalize something as variable as this is ridiculous in the finicky world of junky fly fishers.
Final note: when I'm not tying my own flies I'm buying them where they are cheap and of decent quality, or where they are convenient. Might be a gas station, might be my favorite fly shop, might be GI Joes. When I want info on lines, rods, what river is fishing well and where, etc., I'm talking to junkies. When it comes to deciding, I rely on me, not what some paid to sell something person says. That goes for cars, food, clothes, you name it. Again, the fly shop guy is worth whatever I pull out of my wallet at the time. Don't judge the guy (or gal), let them do their job. Or better yet, maybe you can help THEM.