You're mixing and matching your incredulity. On the one hand, AWS has 40 services. On the other hand, everything is terminated like an EC2 instance... Which really isn't the case.
So, to begin with, most of their services can either be powered down (with chickenfeed storage costs that they could cover as part of the deal) or are outright free. Most things that you fork over money for in AWS can be disabled with some form of networking block. Have code in Lambda? Well, it doesn't get destroyed, it just gets blocked. Have RDS databases or Elasticache? Block access, and perhaps power them down after X time (which saves them to s3, and block storage for AWS's internal use is very cheap - retail s3 is 3c/GB/month). S3 itself also gets your access cut. SES and SNS just stop processing their queues. Things like VPCs and IAM are free to begin with. The costs of keeping these things running behind a block is trivial compared to the overage charges they already routinely waive.
And then we come to EC2... and the story still isn't 'must be terminated'. EC2 instances can be powered down and ELB access blocked, leaving the config all in place and the instance's drive saved to s3 (which is where AMIs and volume snapshots/unpowered instances live). Yes, you will lose data in RAM, but you just get the account holder to accept that the machines can be shut down by AWS, just like already happens with spot instances. If the client opts in to capped pricing, then they can take that into account and design their system around the sudden downing of the instances.
I certainly didn't say everything is terminated like EC2, so I don't know where you're getting that from.
And it looks like we agree: any attempt on Amazon's part to create something like this would be complicated and would still not remove the risk of data loss. An service interruption is, of course, a certainty.
So as far as I can see, the feature still doesn't make much sense. It's only really useful to people who aren't doing anything in Amazon that matters.
So, to begin with, most of their services can either be powered down (with chickenfeed storage costs that they could cover as part of the deal) or are outright free. Most things that you fork over money for in AWS can be disabled with some form of networking block. Have code in Lambda? Well, it doesn't get destroyed, it just gets blocked. Have RDS databases or Elasticache? Block access, and perhaps power them down after X time (which saves them to s3, and block storage for AWS's internal use is very cheap - retail s3 is 3c/GB/month). S3 itself also gets your access cut. SES and SNS just stop processing their queues. Things like VPCs and IAM are free to begin with. The costs of keeping these things running behind a block is trivial compared to the overage charges they already routinely waive.
And then we come to EC2... and the story still isn't 'must be terminated'. EC2 instances can be powered down and ELB access blocked, leaving the config all in place and the instance's drive saved to s3 (which is where AMIs and volume snapshots/unpowered instances live). Yes, you will lose data in RAM, but you just get the account holder to accept that the machines can be shut down by AWS, just like already happens with spot instances. If the client opts in to capped pricing, then they can take that into account and design their system around the sudden downing of the instances.