It's like the duality of modular code. If you want to manage one change in a lot of places, it's easiest to change it in the one module that everything else sources. But that means that one change to that module can take down everything. The alternative where you copy+paste the same change everywhere is the most resilient to failure, but also the most difficult and expensive.
AWS provides a lot of modular, dynamic things because that's what their customers want to use. But using each of those things increases the probability of failure. It's up to the customer to decide how they want to design their system using the components available.... and the customers always chose the easy path rather than the resilient path.
The great thing is that with AWS, at least you have the option to design a super freaking reliable system. But ultimately there's no way to make it easy, short of a sort of "Heroku for super reliable systems". (I know there are a few, but I don't know anything about them)
