The root of all this is that it is sold as a service an management do not give a stuff. IT is not their problem if it goes down they just quote SLAs et al and phone their account manager. No one really cares in the way they would if it was on prem. There you can scream at technical staff and play the blame game. Once it is in the cloud and something goes wrong, shrug shoulders, complain and a few ineffectual meetings, job done. Repeat every time it happens and continue to pay because it is too difficult now to do anything else.
Yes you can mitigate to a certain extent but the costs become prohibitive, significantly more than well managed on prem solutions. And that is where the second major point comes in, cloud is all recurrent expenditure driven and looks good on the books. This obsession with converting capital into recurrent keeps accountants happy as there are no lumps (just an ever-increasing expense). The ultimate cost to the business is ignored, it is just like everything else in society where the monthly payment is king. It does not matter if it costs four times the cost of owning it. Each payment looks small so everyone is happy,