I think it outsources a slice of that effort (rack, stack, cool, basic networking) for all the AWS services and a lot of the server administration when you choose managed services.
It does not eliminate all learning curve, but the learning curve to get a static site hosted on S3/Cloudfront is a lot lower than the learning curve to do the same on prem starting from bare metal.
It does not eliminate all learning curve, but the learning curve to get a static site hosted on S3/Cloudfront is a lot lower than the learning curve to do the same on prem starting from bare metal.