Cloud popped up mostly due to ease of use. Its a lot easier to hire cloudops engineer with somehow enough knowledge to deploy something on the cloud than someone who will be managing a datacenter and have it running.

The later ppl still do what they did, they just work for Cloud Providers making probably quite a bit more than they did previously.

IMHO its a win win situation for everybody. Less skilled engineers can be “productive” and former sysadmins have huge salaries.