Madara can still be revived.
Notice he still has the Rinnegan, the key to using Rinne Tensei No Jutsu.
If Obito so willed it, he could easily revive Madara, and live.
Although that seems unlikely, after what Madara attempted.
I think Madara has something planned, I can only hazard a guess, but his calm attitude to not being revived is highly suspicious.
Seems like he's up to something.
Honestly, I'm glad Obito is not dead, but I'm getting a little annoyed at the relentless D-riding by certain NarutoBase members.