Here's what Gruber has to say
I think that sums up what's occurring, you cannot say its people living in the past, or that its just some fringe users, or typical frustration that we see every roll out. There seems to be a lot of hard core, dedicated mac users who are dismayed
Most of them were already dismayed going into the event (for example, Marco Arment). They are dismayed because they think Apple is focusing too much attention on the stuff that is making them the most money, and not enough on the stuff that is still a very nice side business for them.
In terms of the Mac, even Arment concedes that the MacBook/MacBook Pro is where they make most of their money from Mac sales. So naturally when they do commit resources to the Mac, they are going to invest it in the part of the business that will bring them the biggest returns.
This doesn't necessarily mean Apple will never make a new Mac Pro, or update the current one. It just explains why the biggest priority is working on the MacBook lines when they do invest in something new or interesting.