Amazon does have vendor and seller managers who are allocated to specific vendors/sellers. I'm surprised that for a $2.4M/year AWS customer (presumably with the highest support level) that they wouldn't have a similar setup. That said, having personal attention from a manager is definitely not the same as getting features actually built for you.
With the highest support level you do receive TAMs and Solutions Architects within AWS. They can add feature requests and make sure that influence is added for you and follow up directly with Product Managers to explain why a feature is important.
But, sometimes a high amount of spend on a service isn't really much more than the average. For instance, if you spend 200k/mo on a niche service then you'll get a ton of say in how things move forward, but if you spend 200k/mo on EC2 you might not be able to strongarm anything.
I agree, at 2.4M/year, i'm surprised you don't get more. we spend about 150k/month on Azure services, and it seems like we get a lot more service and roadmap influence....
In my experience a lot of it comes down to how effective their account team is. A good one will communicate with and work to influence the product management at AWS and set up meetings to discuss things as necessary. A bad one can get feedback from the customers they are assigned to and never do anything with it, or send off an email and never follow up.
Azure does a pretty good job of engaging with you, though it's more of a support role to help you during setup and less about feature requests. I'm sure they do those too, but prioritizing them would be a black box.
I've come from an organization with a $250K monthly AWS spend. It was impossible to talk to anyone without spending an additional $25K/mo for a support contract. Insane.