Skill, but mostly due to the company not investing in the time to train to do it right. The company just wants to start next week by saying "flip the cloud switch" and immediately see their costs go down, without any outages and without putting in due diligence.

And sometimes the CEO/CIO/manger is too busy to coordinate training because the decision maker is busy on their "cloud provider training" for only them, in a Swiss Alps super swanky spa and resort.