[sanswork]

Right direct sales is not advertising. The rest still is.

You're missing a step though. There is no consumer pull for new products so there is no reason for stores to bother with them even if the owner thinks it's a great idea. The demand isn't there

[ndriscoll]

They have a similar reason that the product developer had to make it: they have customer empathy, can identify a good product that satisfies a need when they see it, and know how to explain it to customers.