The point you miss, and the main reason why many companies do not wholesale convert to linux/oss instead of Windows systems, is that Linux and OSS do not, as a rule, come with a comprehensive technical support system. Companies pay big money to MS and various software manufacturers in order to have support (or even 24-hour emergency support) to which their underqualified IT staff can refer actual problems for resolution.

When companies are willing/able to spend decent money to hire qualified individuals for their entire IT staff, who can research and repair all sorts of system issues on their own without a backbone of help desk support from the OS software vendor, then you can see them work towards Linux/OSS for the vast majority of workstations on their networks.