> . . . or the problem is inherently complex.

You're close. Put another way, "inherent complexity is the problem."

What I mean by that is, the more your system is coupled, the more it is brittle.

Frankly, this is AWS's issue. It is too coupled: RDS relies on EBS, the console relies on both, etc. Any connection between two systems is a POF and must be architected to let those systems operate w/o that connection. This is why SMTP works the way it does. Real time service delivery isn't the problem, but counting on it is.

Uncouple all the things!

Surely true, but that's the purpose of a system in the first place: to manage complexity and make it predictable. You could argue that we have such a system in place, given how well the Internet works overall. The fact that this system has problems goes against what I believe is fully evident proof that such a system can, in fact, work even better.

We're not talking about a leap in order of magnitude of complexity here—just simple management of common human behavioral tendencies in order to promote more reliability. "The problem is inherently complex" is always true and will always be true, but it's no excuse for not designing a system to gracefully handle that complexity.