There are free software exchange clients, and it's an open platform. Do the math. :)
The truth is that the baked-in software stack is never going to be what sells this phone. If what the user wants is an expensive, high end, pocket-sized browser appliance, then the iPhone has already cornered that market. Android is trying to be a platform. The extent to which it succeeds is precicely that to which criticisms like yours miss the point. If there are important things that it can't do that aren't addressed by the developer base, then it will fail. If not, then it wins.
I'm sure this is Microsoft's fault - it's not like they are going to offer up a portable mobile outlook or owa integrator.
But I wonder who this hurts in the end, device sales, or Exchange use by SMB's ? - I'm guessing a little bit of both, mostly the latter.