No, they don't. They do like choice in the hardware they buy, and many of them find it convenient to use the same OS and software at home they're familiar with from work. The open hardware architecture model adopted by IBM/MS drove an explosion new companies manufacturing PCs, components and peripherals, giving them those choices. That in turn drove developers to create software for that platform. IBM's dominant position in the business world back in the early 80's meant that there would probably be a computer running an MS operating system on their desk at work.
Most people just buy whatever is on the shelf at the Store.
Like I said the majority of PC users don't give a crap about IBM mainframes.
Then ask them what operating System it has, and they may tell you Windows, you ask them which version, and most don't have a clue.
When their computer acts up, they what to buy a new one, they almost never repair the old one.
I work for a VERY large business, and a good portion of the employees don't have a clue about whats inside their work PC.
P.S. The backend server is running on OpenVMS, but this is well hidden.