Fast forward to today, and now it would be a serious undertaking with serious risks to move off AWS, not to mention the costs of building up the staff and assets to reimplement their requirements in parallel of AWS until reasonably confident they can flip the switch and still have an operating company afterward.
So, they're probably stuck - beholden to Amazon's whims and pricing mood of the day. They've bought convenience from Amazon in trade for massive technical debt, one which may be even more costly to get out of... Or impossible.
AWS isn't going to get any cheaper in the future..
Those free AWS credits Amazon gives students really pay dividends.
The “whims” of Amazon’s pricing are no more unpredictable than the pricing “mood” of your colo or your hardware vendor.
I agree that it would be a serious undertaking to move off AWS today. But it's probably also going to provide marginal benefit. No one on the finance side of their business is probably losing sleep over it. If/once it makes sense to move off then the finance dept will tell the eng dept they need to reign in infrastructure cost...and eng will do that.
Arguments like yours are why business people tend to roll their eyes and ignore engineers when it comes to anything outside of engineering.
Not trying to be dismissive, but you are so far from the mark I don’t know where to start...