Yes, some of them are "middlemen". If you use the term as it is supposed to be used, a middleman is someone who gets on the supply chain between the authorized wholesaler and us, the reseller. In some cases though, the middleman jumps in the chain between the factory and the reseller when the factory as a normal course of business deals directly with the reseller. In both those cases the reseller will not be getting the lowest price. And in some cases, you will find two middlemen jumping on the supply chain.
The trick is to get a price on product which is the least watered down; no or only one middleman
In the case of drop shippers,(90%) are a middleman but sometimes that added expense is worth the cost. This eliminates shipping(From dealer and to customer.) and storage fees. But many and most times it will be a hindrance to the profit.
The best way to determine if a supplier is a middleman is to check prices on eBay and then use an eBay calculator to determine if there is a profit in comparison to other item's closing price. EBay's completed sale prices are commonly just over wholesale on the average, with room for profit but not much on most items.