This only really applies to fully-managed services such as Heroku. Every other cloud still needs a DevOps person according to my experience in many companies.
Yes, but one cloud devops can do what 10x what sysadmins, hardware and network engineers can do.
Just security alone, in terms of managing access to all of those resources, various forms of backup, across regions ... it's just out of reach for most organizations.
This only really applies to fully-managed services such as Heroku. Every other cloud still needs a DevOps person according to my experience in many companies.