Then again, I worked for AWS for years, so maybe I'm just used to thinking this way so I'm not really surprised by it.

You still see paying for bandwidth with residential connections, though some operators (like Comcast) are trying to do away with it.

This is just the static picture though. What's harder to predict are the consequences of some innocuous looking code change.

What I'm saying is that for a hosting architecture to make it difficult to predict the cost of any code change is a downside compared to an architecture that makes such predictions easy and intuitive.

Of course you will try to mitigate any downsides and learn what you can from any mistakes. But unpredictability makes learning far more difficult than it should, which inevitably means a waste of development resources.