They mention two key differences. The first is just that Amazon is arguably more dominant than any physical distributor, and has more power over offerings.
The second is that if you make a new product for a retailer, the retailer usually has to invest in you to some extent, by giving you physical space and buying your product for resale. So, there's some shared risk and for developing new products. Amazon, on the other hand, doesn't need to give you anything to see how a new product will play out, so it might have too much of a position of power.
I buy the first, not the second. Retailers often charge consumer packaged goods companies (CPGs) for preferential placement in aisle and carry no risk on inventory. The bigger the retailer (eg. bestbuy, walmart), the more likely they can assume no risk on inventory with a full return policy to the CPG. Best Buy just rents out space on their store floor to individual brands.
They mention two key differences. The first is just that Amazon is arguably more dominant than any physical distributor, and has more power over offerings.
The second is that if you make a new product for a retailer, the retailer usually has to invest in you to some extent, by giving you physical space and buying your product for resale. So, there's some shared risk and for developing new products. Amazon, on the other hand, doesn't need to give you anything to see how a new product will play out, so it might have too much of a position of power.