I think this is really great for getting stuff up and running as quick as possible, maybe if you're just starting out, but I'm really surprised at some of the things said. Maybe if this is a site that you run on the side.

Doing test/staging on a nano and then pushing to production on an m5? What? Like get ready to troubleshoot random issues completely unrelated to your code. And then equating different AMI's to containers is vastly oversimplifying things.

With docker I can just get up and running on my local box and every dev I share this with has the exact same environment and config.

I can package up those images and send them up to ECS/Kubernetes and not deal with the same headaches. The learning curve is a bit steeper, but absolutely worth it.

I walked the same path here (starting out with single VMs for environments, installing services locally on my laptop) and the headaches down the line are not worth it and it isn't even a case of over-thinking the solution. You don't need to ride the cutting edge but modern tooling saves a ton of time.

It was a PITA migrating our old VM stuff over, but absolutely worth it. If you don't want to deal with maintaining systems there are other solutions mentioned ranging from full PaaS to something like GKE.