All great points. I have seen in company of smart people CIO/CTO would freely up admit "Look we know cloud may not be cheap or easier to manage but this is the direction we have taken since we are getting out of owning or managing hardware/datacenter"

So it is not like one can dazzle decision makers with any logic or hard data. They are just announcing the decision while calling it a robust discussion over pros and cons of on-prem vs cloud placement.