That is what annoy on apple world, while in iPhone/ iPad I trust apple to bring me the best components, I trust their engineers to "tell" me: "listen this hardware is all you need in this point int time, and when a better one will come that we think will make an impact, we will give you new gadget"
In computers this is not the case, people want the best hardware there is all the time.
People know and understand CPUs / gpu, and know when they need a good one or better one.
They want flexibility, so in the case of window machine you can swap the CPU the moment intel release new CPU.
In apple world they treat the desktop as iPhone, I have to wait for the whole package.
I can barley understand it in iMac ( as long as they change iMac every year with the best components...), I can't understand it totally in Mac pro!
Imagine that people in the entertainment business in Hollywood are now stuck with two years old machine, can't upgrade can't add components, just because apple don't think that it is the "right" moment for them.
This is a joke.
If I was using Mac pro I would seriously had to consider changing back to pc.