They might be niche to MS - I'm not sure - but they're definitely being targeted.https://youtu.be/BzMLA8YIgG0https://www.microsoft.com/en-us/surface/devices/surface-studio/tech-specs
Add to that the new Surface Book and the expected updates to the Surface Pro - that's extraordinarily high end specs for a non-pro user and they are poignantly not that great for gaming (you can, but it's not a key experience) which is a nice that might otherwise be prepared to play in that price range.
Yes, it's a start - it's an iMac on steroids for want of a better description, and that's not the not the same as Mac Pro, for example, but the Surface Book 100% targets the MacBook Pro.
MS has had great success with Surface and they also benefit from the closed architecture that Apple has had for so long as a major plus for OS X (Windows biggest problem has always been trying to support all the third party hardware out there - something it does remarkably well overall excluding certain releases we all know about).
If Surface Studio has any real level of success, you can expect them to look at even higher spec hardware that would be in the Mac Pro space.
So, yeah, it may or may not be niche, but it's definitely targeted by them and I think more so that Apple currently.