There were good reasons for not not announcing the price, not that it wasn't a disappointment that the issue was completely avoided.
It all depends upon their release strategy when the device debuts. Do they favor rapid adoption rates in an attempt to ride a second wave of initial interest in the Xbox platform, or are they more focused on keeping the division profitable?
Production costs of the actual unit itself aside, there are still things to recoup from the R&D of the device and the marketing effort going into selling the public on the device. These are far from invisible costs.
But if they really want to keep the add-on "competitive," they will have to consider a $99 MSRP, due to Move bundles, even though Kinect is a one-time single purchase as opposed to Wii or Move controllers. Extra controllers have always been a good revenue stream for console manufacturers and with Kinect, MS doesn't have this extra source.
A $149 price would be an attempt to offset that advantage and I could see their PR take on this being a competitve price by comparing it to the price of a Move starter kit with an additional controller. Not entirely unreasonable, but it's still $149; almost the price of a console (or the price of the current inventory clearing discounted Arcade).
Of course if they would prefer to just skip the comparatives and just boil things down to the one factor most consumers will look at in deciding WHEN they want to adopt, then they should go with a sub-$100 price to draw in a healthy amount of buyers with a casual interest (which is really the demographic that Kinect is targeting rather than the core audience based upon what they showed at the conference), eat their losses on initial investment and recoup with initial soft sales.
$60 for most of those initial titles seems a bit high considering the fast turnaround time/lower budget appearance, so who knows. A lot of people will buy them regardless for the lack of anything better to play with Kinect. It's not like people will be paying $149 just for voice and gesture commands while using Dashboard or watching media.