This is not an unreasonable point, but I will note that I was partly using “AWS” metonymically to refer to a whole cluster of technology decisions surrounding the current wave of “cloud” everything, and I was also partially referring to the purer “have you been part of a full-scale service deployment with real users” aspect—there's a bigger difference between “operating a service when there's hundreds of thousands of requests from real people hitting you and they really count” and “operating a service for a random who-cares project” than there is between, say, “having a precise understanding of how Ruby behaves in a business-critical backend” and “having a precise understanding of how Ruby behaves on your laptop”. Lacking experience or even just lacking legibility of experience on the former seems to close a lot of doors, and that means you run into the “need experience to get experience” cyclic dependency on a critical subset of what's needed, regardless of how good your other skills are.

I recently had a job for exactly a week before the company decided I wasn't working out. One of the things they had me doing was logging in to Azure and trying to debug something - even though Azure never came up during the interview process, only AWS. It seems they didn't recognize there was any difference between them.