In a way. Resellers typically incorporate a company's AWS organization into theirs, and via resource sharing of savings instruments, are able to pass on savings to their customers within their portfolio. Since they have an AWS organization that is comprised of many companies and their AWS accounts, they are able to negotiate special pricing arrangements with AWS (typically in the form of an EDP) based on the total spend of that consolidated organization.
We use similar instruments but allow you to maintain the independence of your AWS organization for what is usually higher savings.
Why would they be in a good negotiating position with AWS, given that they have to be on AWS to even exist in the first place? I don't get why amazon would ever negotiate down with these guys, they're the ones who absolutely need the product.
Like any reseller, they are aggregating demand, and then negotiating volume discount with the provider. Resellers will work with multiple cloud providers.
In principle at least, customers can become loyal to the reseller and their value-added services, and the reseller can influence their clients to move to other providers. Obviously hosting is one of the stickiest SaaS services around since switching costs can be monumental, but the theory still applies.
We use similar instruments but allow you to maintain the independence of your AWS organization for what is usually higher savings.