In web dev shops it's typically Mac for the workstations and Linux servers (in the cloud or bare metal). Maybe the accountant uses Windows and some devs use Linux but generally nobody uses Microsoft for hosting anymore (in this field).
Plenty of sys admins jobs there, they're just called something slightly different (devops? Cloud engineer? Etc.)
Plenty of companies using Macbooks as their primary machines. Though as soon as the finance/accounting departments grow beyond tiny they frequently get exemptions to be able to get Excel on Windows - all other options are sub-par.
It makes me wonder if there are any fully, just Linux corporations, no Windows.
I don't know if this is still the case but Redhat had strict rules requiring all servers and desktops to be RHEL. By strict I mean they boasted in front of my coworker and other customers there for the RHCE and their own employees that anyone deviating would be fired on the spot. But this a long time ago RHEL3 timeline.