This covers not just running the services, but keeping up to date with security updates, scaling the systems, feature additions, bug fixes and keeping up with the state of the art.
Services like RDS are an amazing net cost saving for small to medium users. Something like Cloudfront would cost you a million just to get going. Raw EC2 is nearer break even.
We've used CDNs in the past, way below a million/year for a medium, growing startup. care to elaborate?