Why did the SDs wait?

I started talking about this in early February, when no one was talking about it, but since then it's been all over the news. What will the SDs do? When will they decide? My superdelegate compact, though it makes perfect sense, never gained any ground... even the good people at Demconwatch, who decided to keep track of the "Pelosi Club" (those SDs who pledged to vote for the delegate leader at the end of the primaries), could only come up with a whopping nine SDs who would join Nancy Pelosi in saying that democracy should win out over the SD vote.

It seems that most of the remaining 200-plus uncommitted SDs are biding their time until June 3, and then will likely pledge one way or the other. But isn't it just arrogance that allows them to "see how it all turns out" when the delegate leader (Barack Obama) has been known since his great success in March? What they're really saying is, "We want to hold onto our SD prerogative for as long as we possibly can, even if drawing this campaign out does nothing but bloody our eventual nominee and help John McCain win in November." Somebody please get these SDs to sign a NEW compact: On June 3 or 4, hundreds of them should back the delegate winner, namely, Barack Obama.