The article doesn't actually imply (though people might wish so) that the described TPU is intended to ever be a product available to others.

It's a post saying "that's how we do it" that serves a bunch of political and PR goals, but it's quite likely that this will stay an internal technology; maybe available indirectly as a cloud computing offering - in which case they'll give the specs and price of the whole solution, not of a particular model of TPU chip.