Obscure and complex are different concepts. I'm part of that "secondary consulting market" FWIW, so I'd like to think I know a thing or two about it.
Does AWS have high-margin prices? In aggregate, somewhat, but this is mostly driven by the big ticket managed enterprise items: Aurora, Redshift, Quicksight, probably Fargate, etc. A lot of their more popular stuff (S3, Lambda, …) offer incredible value for very little money. EC2 is the exception I believe, because I understand it to be high margin for how popular it is. But EC2 pricing is one of their simplest ones.
Could AWS simplify some of their pricing? Yes, probably. There's always room for optimization. Personally for example I'd like to see their pricing be global rather than different by region (with understandable exceptions for govcloud and china).
Is AWS making its pricing complicated for nefarious purposes? No, there is no evidence to support that.
AWS pricing absolutely is not simple. It's a part of the AWS stack. You need to study AWS's events/signals system to be able to write apps that make the best use of AWS's interconnected stack. You need to study their APIs / SDKs to really understand what you're able to implement. And you need to study their billing systems to understand how to implement apps that run cheaply, and be able to predict potential runaway costs.
It has to be a part of the design. That's why you may want to hire consultants for it: People who understand it better than you do, and will be able to assist you in reducing your costs.
It's just another kind of optimization. Maybe some software engineers don't like it because it hits them where it hurts (the wallet) when they don't do it right, rather than be able to brush it off as they usually do.
It's much easier to ignore the waste produced by, say for example, the 3000 javascript dependencies shipped with the fat, unoptimized electron app they ship on their users' desktops, that do a ton of unnecessary expensive computing; when all that crap is client-side and it's the downstream user's electricity bills and CPU time that's being used.
It does mean it's not simple though.