Actually folks John Deacon was in the group in 1998 for the performance of "The Show Must Go On" which is ended up on "Greatest Hits III". I think people seem to give the impression that he is out but it is not like they have really done anything new yet so who knows in the long run? Plus who says he wouldn't join again after B & R did do something new, eh?
That performances was 1997... he quit just a bit after that. And I don't think he's coming back. He has made it clear that Queen isn't Queen without Freddie, and he's done. He did a few things after Queen, like the FM tribute, Made In Heaven, No-One But You, and that last performance of The Show Must Go On in '97. If he's happy being a stay-at-home grandpa, then let him. He deserves it.