Containerization solves a few things. One big one was the container image as a packaging model. As customers struggle with dependency management or installing native packages (RPMs) we're basically faced with reinvent Dockerfile... or just use Dockerfile. This is an over simplification of what's happening, but that was the initial spark of this, many many cycles ago.
I think this is still going to be really valuable for folks, but what you are looking for already exists I'd say, and is Fargate.
Btw, ppl shouldn't be downvoting this, its all very valid.
- Chris, Serverless@AWS