[swypych]

This.

It's sad to say but people are not rewarded by going with a perceived riskier option in an effort to save a couple 100k.

You go with what works and proven, and with what will make your life the easiest. If AWS goes down, then its much easier to explain why. If "Big Bill's Lowcost Cloud Solutions" provider goes down, then your entire judgement will be questioned. Even if Big Bill's Cloud solution is equally or more capable and only half the cost.

[karatestomp]

Yep, it's risk aversion at the individual level. Your solution you fought for breaks once? That's associated with you, personally. AWS breaks three times in the same time period, or ends up costing a ton more than expected, or whatever? Well it's an "industry standard" so no-one gets the blame, even if it gets bad enough that a change (how about Azure!) is initiated.