If something I'm responsible goes down to the point that my stakeholders are complaining (which is something seriously wrong), they are not going to be happy with "oh the cloud was down, not my fault"
If AWS is down or not it meaningless to me, if my service running on AWS is down or not is the key metric.
If a service is down and I can't get into it, then chatter on things like outages mailing list, or HN, will let me know if it's yet another cloud failure, or if it's something that's affecting my machine only.
Right, there should be an "alliance" of customers from different large providers (something like a Union but instead of workers, it would be customers). They are the ones that should measure SLAs and hold the provider accountable.
If not happy with the results switch.
But I'm leery of any business who's so dishonest they fear any outside oversight that brings repercussions for said dishonesty.
"If not happy, switch" is silly - it's not the customer's problem. And if you're a large customer and have invested heavily in getting staff trained on AWS, you can't just move.
So unless regulation gets implemented that says otherwise, there's zero incentive for any company to maintain an accurate status page.