Why isn't City Hall in a village?

Why isn't City Hall the anchor tenant in Newton Centre or another transit-supported village? It's a shame that city staff can't take transit to work, that they can't (reasonably) walk to lunch or lunch-time shopping, that the nearly all-day activity at City Hall isn't adding to the vitality of one of the villages.

Possible, long-shot scenario: rather than renovate the rather decrepit City Hall, tear it down in favor of a use that it less transit-optimized (day care or an elementary school come to mind). Build a new City Hall in Newton Centre.

Now that would show a commitment to livable streets!

Update: My charge that City Hall is not served by transit is inaccurate. There is a bus line that serves City Hall. But, shouldn't it be closer to one of the many T stops in the city?