Apple is becoming a consumer-oriented company with their focus on iPhones, iPads, and lower cost portables like the MacBook Air and 13" MacBook Pro. These are Apple's top selling products, by far!!
This was Steve's reasoning. The Mac Pros were just not selling, numbers in the thousands, not multi-millions.
That said, I think that Apple's pro products like the Mac Pro are among Apple's highest quality, best built machines around. The Mac Pro is like a tank compared to any similar offering like HP or Dell, and requires far less service in the end, and reliability is near 100% uptime on these machines.
Apple going for a more "hub-like" Pro computer offering external expandability instead of vast internal drivebays and swappable processors, PCIe slots, and graphics card options is a step towards a more consumer-like pro machine. Apple is getting rid of the tank and going for something more like what the G4 Cube was, essentially this IS what the new Mac Pro is...a 2013 G4 Cube (with dual intel processors). It will offer Pro power, but the internal expandability is practically nothing. I think the people in the Market for "this new" Mac Pro were wanting something with a little more expandability, knowing the machine would be smaller and more consumer-like. In My opinion, it is more a Pro-Mini than anything, Not a Mac Pro. We will just have to hold our breath to see what price Apple is asking for it!!
So, yes, this is the direction Apple is headed. Two other moves they made in this direction were nixing the 17" MacBook Pro, and not offering Matte display options for the Retina MacBook Pro...as well as nixing the 30" Cinema Display and all Matte Cinema displays as well. I don't like what Apple is doing here -- these were all great, top=notch, well engineered products. Guess Apple just wants to sell 10 gillion MacBook Airs and 100 million iPads instead and rake in the dough.