I don't think that's it. Those who migrated their EC2 apps to ECS/EKS/Fargate/App Runner have already migrated, so there is diminished returns in pushing those technologies.
The same goes for serverless. The whole world already adopted this to it's full extent. Those who want/can use these services, are already running these services, and AWS is already getting better utilization rates from their idle computational resources from this.
These are not fads. They are already infrastructure.
What we are seeing is additional high-level services being released to meet customer demand. There's now a massive need for training and running your custom private LLMs. There is absolutely no justification to skip the revenue you can generate by serving these markets.