What makes you think that? Those inflexible workers are also those who make the purchasing decisions. A shop full of Windows admins will not switch to Linux unless forced to (and vice versa).

And many will eventually be outsourced. In fact, systems administration as a profession is on the downswing due to the cloud. This site itself is largely focused on "disrupting" inefficiency with automation.

Not only due to cloud; even if you have local bunch of immutable OS instances like CoreOS or RHEL atomic running containers, you don't need a big staff babysitting server OSes.

Yes, conflated cloud and containers in my head when writing that comment.