I'm sure there's lots of stuff but you can't really stop using AWS unless you stop browsing a pretty large chunk of the Internet.

Not really what we're talking about. We're talking about being a direct customer of AWS vs other providers.

Relief from the IT procurement policy antipattern.

Many of their managed services.

Like? Lots of other people provide managed services as well nowadays. I'm not an expert on the matter, but I really feel like anything they offer probably has an alternative at this point if you don't want to use AWS.