The bike industry has always been a crappy industry - low margins especially at the retail level. Specialized, for example, makes a million different bikes for every possible intended purpose but you couldn’t sample even half of them at even the largest Specialized dealership.
Couple the margin problems with low wage, under-trained employees and this is what you get. Most shops want to close the sale on something that they have in stock as there is an urgency to rotate the stock so they can meet the buying quotas imposed on them by Specialized, Trek, etc. so that they can maintain their dealership status and discount levels.
I feel for shop owners. It’s a tough grind.
It’s probably hard with inexperienced cyclists. They don’t know exactly what they want so they end up relying on the inexperienced staff and the availability of what is in stock. There are also lots of judgement calls in bike purchases. If a rider is between a 56 and a 58 and the shop only has a 58 in stock then the rider is going to be pushed towards a 58 rather than the optimal sizes.
I think the other issue is that people are cheap. They always want a discount. Or, they don’t put a high enough value on custom service to want to pay for it. I bet a lot of $1000 bike buyers don’t realize they need $150 in shoes, $200 in clothing, $100 in accessories, and a few other things to make cycling a good experience. And after all that, how many of those customers will spend $300 on a custom fitting?