I've never worked at google. Do they just let each team go with their own crazy hardware setup? Or maybe two separate systems, one internal and one external? That seems a little wasteful (they have the money, so whatever).
But wouldn't programming against a big unified api be a bit more, well, sane? I can see really sensitive stuff locked away on its own hardware, but the search front end? why not serve some JS or provide chrome downloads from a giant pool of common hardware?
Things grow organically, and they might be technically locked into a specific layout right now, that's totally understandable. But, unused capacity is just capital depreciating steadily away with no gain. Soaking up every spare cycle doing something useful should probably be somewhere in the company goals.