As an outsider, it looks like MSFT does not grasp kernel performance as a super important feature of Windows. They add so much bells & whistles over the UI, but the inside sucks release after release
As someone else posted in this same thread: is modern Windows substantially slower than the OSes it competes with (in anything other than a few uncommon niches)? If it's more than a few percentage points slower for anything but rare scenarios, I'd be surprised.