A fellow photographer just came back from a 6 week trip out of the country. On one of his flights, there was an onflight magazine ( I think he said that) that had an article on Adobe and their photo software. What he iterated to me was that it said CS4 had untimely release in relationship to LR2 and the economy and sold in very small numbers. They have improved it into CS5 but have decided to stall the release of LR3 until next fall to encourage a greater amount of sales with CS5 so that they are not quite so much in competition.
I don't think they are in competition myself as they work so well together but from a marketing standpoint this may still be true - I just don't know.
It might also explain LR3B2 which still seems to have issues according to what I read on the LRforum.
Ultimately I don't care, not in my case as I'm not in a hurry. I like LR2 a lot and intend to get an upgrade to CS5 anyway so my fondest hope is that Adobe uses this time to make LR3 even far more incredible than we anticipate.
I cannot verify any of this but the person who told me this is not the kind who cares to create rumors, he's not very close to any of this and just found it an interesting article.