I think the Mac Pro exists for reasons independent of directly making a profit. Though Apple would always like to make a profit, of course. It's a combination

I think the Mac Pro exists for reasons independent of directly making a profit. Though Apple would always like to make a profit, of course. It's a combination of a halo car and a triple whopper. A halo car is a statement of intent from a car company. It's showing off "here's all our coolest stuff, and the direction we think things should go", while being impractically expensive and bought by almost nobody. By putting out the fancy new Mac Pro, Apple reassured professionals that it cared about them, and presumably that's making people less likely to nervously shift away from the platform even if all they actually need for their own work is a laptop or Mac Mini. The triple whopper, famously, mostly existed to be a conspicuously more-excessive product that made the double whopper look more reasonable in comparison. If the Mac Pro exists at $6k base, buying a reasonably specced out iMac suddenly looks downright responsible! Both of these things are good for Apple's bottom line.