I'm not sure about that analogy (the central bank better care; if billions go missing I expect them, for the sake of our economy, to find it and not just print more), but you're right that Google should not care about its own PR. As for everyone else's PR, it seems that the servers are either having problems right now or Google is once again re-tooling the system.
Can people check http://www.xenyo.com/seotools/verifypagerank.php pls. Seems to be working for me....
so many PR problems this days...now, even those PR checker tools has problems. maybe they did not update as Google updates PR LOL.
Don't get fooled... There is a difference between PR0 and PR N/A. Pagerank is not currently available on Google servers.