>Would people seriously prefer to run a commercial studio and Pro Tools on a windows machine?
Yes. A specialist system integrator can sell you a Windows machine with reliable low-latency audio performance and modern components. A lot of people can make do with a 2013 Mac Pro and don't want to deal with the inconvenience of switching; plenty of others have switched because they simply can't tolerate working on a machine with an Ivy Bridge processor and a maximum of 64GB of RAM.
Yes. A specialist system integrator can sell you a Windows machine with reliable low-latency audio performance and modern components. A lot of people can make do with a 2013 Mac Pro and don't want to deal with the inconvenience of switching; plenty of others have switched because they simply can't tolerate working on a machine with an Ivy Bridge processor and a maximum of 64GB of RAM.