it is extremely expensive to order from US in Europe, shipping and taxes etc.
using an intermediate in this case helps alleviating the shipping expenses, because these buy bulk amounts and get retail discounts. Here in Europe, the retailer pays approx. half the market price before taxes. So what the producer earns more if he sells directly to the customer, because he sets the price margin. Retailers cannot increase the price to whatever they like.
So if producers want to increase distribution, they either use retailers (even GW as a large company who sells directly needs retailers for distribution), if they want to sell directly they should facilitate this by lowering transaction barriers like taxes and shipping. small companies can't afford to do that, so they are somewhat inhibited when it comes to distribution....
The idea is to increase sales by improving distribution - the profit margin compared to direct sales is thus shared with the retailer. The idea that with today's online sales options the price can increase deliberately is a bit simplistic....