Go to Google.com and click on the "more" menu and just above the YouTube link, you will see the link to "Realtime."
As you know, clicking on that link will lead you to a dead page. So why didn't Google remove it? I do not know why but I can venture some guesses.
(1) They didn't get around to it yet?
(2) The deal broke off with Twitter so unexpectedly they were stunned and go back to item 1.
(3) Google ticked off Twitter with the launch of Google + which caused 2 and led to 1.
(4) Google has plans to get Twitter deal back very soon and doesn't want to bother dropping it from the menu.
(5) Google has no plans to get Twitter back and plans on replacing it with Google + data very soon.
Those are some of my theories but again, I don't have any more information than you have.
One thing Google did add was a notice that when you go to a legacy realtime search result page (yes, I save URLs of search result pages), you get a message that the results are no longer available.
Anyway, I am terribly missing the realtime Google results so I hope they come back soon.