True... however, a moderately large website I have access to analytics has about 5% of Chrome users using something older than 11. It's possible to install Chrome without enabling the auto updates, so exactly which versions of Chrome they still support is somewhat useful information, I guess.

More likely, since the versions of FFx, IE, and Safari they support are the versions of another company's product--unlike their own--they feel like they have to be more upfront.