According to industry data the average marine "hobbyist" lasts 18 months. The LFS is not in the business of creating exceptional fishkeepers and hobbyists. The LFS is in the business of selling fish, and equipment. The less you know the easier it is to do that.
More optimistically there is a mountain of information and best practice in this hobby. Most hobbyists don't follow every best practice. LFS people are at best good hobbyists themselves, and at worst not marine hobbyists at all. It's important to not rely on them as ones primary or exclusive source of information, that's not their job.
