Honestly this is what I was afraid of when Mozilla backed off on Rust support and Amazon and others stepped in to fill the gap. One of the main selling points for me to start learning Rust was the truly open-source pedigree - with Mozilla backing it there seemed to be very few perverse incentives going against Rust's goals of having a great developer story.
If Amazon would be in the drivers' seat, that incentive structure would seem much less clear.
To be clear, the Rust Foundation has no influence over the design or development of the language, stdlib, or tooling. Those are duties of the dedicated Rust teams listed at https://www.rust-lang.org/governance/ , and the foundation has no power to determine the membership of those teams.
If Amazon would be in the drivers' seat, that incentive structure would seem much less clear.