Originally Posted by TSBasilisk
There are only two bijuus left: The Kyuubi and one unknown. At this point, it's a race to the finish. Once all the bijuus are captured, Akatsuki can slip into the shadows and use their statue to eliminate their main enemies first, before gradually taking down those who don't care. Coming out of hiding now would just place their entire scheme in jeopardy.
I will just add my opinion.
Maybe Leader wants most of the members dead, and thus he will not lift a finger over his dying members. He needs them to gather the Bijuu, other than that, they may just be a nuisance in his plan since they may search for more power (which is natural, especially for them).
Once he has all the Bijuu, he wouldn't need most of the members. Hidan and Deidara would be quite useless to him later, he would have to dispatch of them anyhow, so Konoha basically did him a favor.
This is just a thought though, doesn't mean it has to be true.