Late to the party, but Im going to agree with Murl.
For the most part, if an SA in a store can tell you where the chinos are, and where the suits are, and if they have any gingham checks this season, and if they can help you get what normal people consider the right size suit, meaning comfortable and not stupid tight or stupid baggy, and even combine items and put together a few nice looking fits based on what most people consider nice looking, they are doing a fine job.
When it comes to half inch differentials, and is the texture of that tie a country texture, so perhaps I should not wear it with this city shirt, thats not normal. Its not wrong, but its not anything most people considered required knowledge to look nice and presentable. Most people dont care about that and dont want to care.
Additionally, many SAs are very good at helping put together a look that would be in the height of fashion. Perhaps GQ/Esquire fashion, and not SF fashion, but its still means they know what they are doing. When we snicker and look down our noses at them because they are not subscribing to our timeless and classic superior menswear knowledge, it is us who have jumped the shark.